Having a good aim in any shooter is always a must if you want to rank or have more fun in the game, as who doesn't like getting tricky shots, right? And missing as few shots as possible is one of the best ways to take enemies down.
Like any other skill, aiming takes a lot of practice, but sometimes just playing the game over and over again can not be the best way to practice your aim, although you're aiming in the game, your focus may be on a lot of different things that happen in an Overwatch match. After you play some hundred games, and you don't seem to improve your aim, you can have developed bad habits that make you unable to improve.
Training your aim can take a lot of time, but a few things can instantly improve your performance if you're out of practice, keep in mind that enjoying the process is the best way to sharpen your skills.
The first step to put your aim into practice is to create a custom match, and while the Practice Range mode can be handy, the custom match will allow you to practice with in-game character models, movement, and maps, being a closer feel to a real game but without any pressure.
A well-known tip is to set the custom match settings to allow only headshot damage and create a match consisting of you against a team full of Anas, Ana is a hero unable to get headshots, so she won't kill you, while you're able to practice aiming at her heads!
You want to set the AI difficulty at hard, even if they aren't able to kill you, they must have a better pathing system and related things, so you'll train with at least a somewhat smart AI. After these settings, you're free to use any map and the hero you pretend to be playing, relax, and headshot.
Playing with friends allowing only headshot damage can be great too, and as noted, the Practice Range mode is okay but not that great, as the robots in there have easily to predict movement. Not being a specialist in reflex training, I'd say that you want to practice in an environment as close as possible to the real game, but being able to do as many shots as possible, as in a normal match you'll train your aim fewer times than in this custom one.
If you never practiced your aim before, try a map that you're comfortable with and stand still next to the group of Anas trying to land these headshots, if you don't know how to aim decently yet, don't try to shot while moving or sky shooting(with Widowmaker), start from the basics and after you see some improvement, increase the difficulty.
Practicing this way can potentially greatly improve your aim, but a problem with this way of training is that you never need to take into consideration the damage you're taking, this is something that you'll need to improve in actual matches, the custom training match is great for aim and aim only, but an Overwatch game is more than just aim, keep that in mind once you get in a game after practicing.
Is crosshair or mouse important to aim better?
Not really! Changing to a crosshair that you like won't do anything but make it look better, after you start aiming better you won't even take time to look at your crosshair, it just happens naturally.
Mouse sensitivity can somewhat affect your aim, but it is not something that will do any significant difference, DPI stands for dots per linear inch and it is how much your cursor will move per inch of the real mouse movement. There are a lot of products that are focused on gaming, and "Gaming Mouses" can allow you to switch DPI directly in your mouse, they also have a higher DPI, but is that any great?
DPI and the usual mouse sensitivity settings will be the same thing, and they're allowing the screen cursor to move more with less physical movement, in theory, if you were a human aimbot you could benefit tons from this, allowing you to clear a whole team in seconds.
In practice, a high mouse sensitivity makes it way harder to aim, while a too slow sensitivity makes aiming easier but not fast enough. High DPI however can be great if aiming is not what you're looking to do, some characters will benefit from it as movement is their thing, like Wrecking Ball or Lucio, and switching quickly your DPI can allow you to have the best of both worlds.
If you're playing a character with the focus of aiming and killing, a Gaming Ultra RGB Chroma Special DPI mouse won't do much, you will have to join the joyful path of practicing.
Is Widowmaker harder to aim?
Widowmaker isn't any harder to aim with, but it feels harder, missing a shot with Widowmaker is more punishing than missing a shot with a character that can further shot a few more bullets instead of having a delay.
Practicing with Widowmaker isn't just about the aiming, as your positioning plays a crucial role in the game, the grappling hook has a great vertical movement that can also be used to take some shots, sky shooting is hard to get right but can give you a strong advantage.
Widowmaker is a hero that will do most for your team when you're consistently taking enemies down and winning your team fights, when this doesn't happen, you cannot contribute in any other way unless you can take down a healer or another character that is giving your team a lot of trouble.
When doing a custom game to train with Widowmaker, you may want to try other bots AI and maybe even consider a hero that can do damage. Practicing sky shooting is also a great thing to do, but the most important, put your ego down and switch when needed, the hero doesn't work with all teams, it is important to know how to play another character!
Is Overwatch harder to aim than Valorant?
Aiming in Overwatch versus Valorant is a topic that can cause a lot of heated arguments! Of course, every person will have their own experience in both games and make their claims based on that, and it wouldn't be wrong.
Overwatch is potentially harder to aim, the characters have a fixed acceleration and with a great difference of model sizes, on top of that, Overwatch also has movement abilities and a Wrecking Ball with no head for you to headshot while it comes to your direction.
The thing when comparing Overwatch to games like Valorant or Counter-Strike is that although they are shooters, there are a whole lot of differences that we end up ignoring, they become apples and oranges.
Some factors in one game or the other could make it harder for you to aim, while for another person that will be easier, and so on, but the thing is, with practice aiming in both games shouldn't be of any problem.
Bad aiming habits
It is easy to develop some bad habits related to aiming, and it can be hard to get rid of them, the first step is noticing them so you can in some way attempt to improve. Some of those may be just newbie mistakes rather than developed habits, but it's good to keep them in mind.
Aiming down or at bad spots
Looking on the floor while you walk or to the sky, or in any spot that you know a player can't be there doesn't help much in a shooter, this can make you get caught off caught. for a foolish reason.
Shooting before aiming
I believe that this is more common than we realize, if you spot an enemy off guard and you have a quick time advantage before they notice your presence, shooting before aiming will just reveal your position and throw away your advantage. This shouldn't be confused with a very good reflex in where you are aiming, this is something that practicing in custom matches can greatly help.
I gave that a peculiar name that for some reason describes it perfectly, this happens when you have a perfect shot that you know you can get but somehow you think twice about it and screw everything up. As a second time noticing, I am for no reason a specialist in the field, but I believe that if you wait to think before you shoot, your performance will be worse than if you just do the movement naturally subconsciously. Sometimes when you have a perfect shot, you may "stop to concentrate" and that can be the factor that makes you miss it.
A way to practice and get over this would be to avoid hesitating before shots, there is an Aim Hero app with a mode that makes targets suddenly disappear if you take too long, this can force you to stop this little concentration over a perfect shot.
Big useless sensitivity
Very high sensitivity can make you miss more shots than getting right, you want a consistent sensitivity, easy to achieve and that lets you focus on just aiming, rather than pushing the mouse back from the top of the screen.
Aiming is very important, but not always you want to shoot after it, sometimes shooting will make you take a fight with great disadvantage, or make you miss a later opportunity, but of course, you should shoot, but know when you shouldn't.
Lack of confidence
It may be not related to aiming but not having confidence can somehow lower your performance, some people can aim perfectly on some heroes but after picking Widowmaker suddenly their aim becomes inferior. Widowmaker is a hero that will often give you a lot of flame from teammates if you don't perform good, and this can be very demotivating to practice the hero and learn how to play it, but the thing is that it is how the process works, you will occasionally get better at it.
Other bad habits
Not necessarily habits, but some of those will be particular to each person, the thing is, being able to recognize what you keep doing wrong, again and again, is the first step to fix it and progress, watching your match again sometimes can show you in another perspective what you could have done better and if there is a mistake that keeps repeating itself. Sometimes bad aim habits aren't related to aim, but aiming is the quickest thing to be blamed when things go wrong, after your teammates.
Software to practice aim
Lately, a lot of applications have gained popularity due to how easy they can create scenarios for you to practice your aim, and adapt themselves to have an aiming feeling as close as possible to the game you play.
If some aim trainer greatly improves your aim in-game, that is good, but sometimes practicing in the actual game custom matches can be better, it is something closer to a real match.
KovaaK 2.0 is a well-known and recommended aim-trainer, released in 2018, KovaaK 2.0 offers a low input delay which is used by a lot of streamers and professional players to train aim.
KovaaK 2.0 has over 10,000 training scenarios, so it can adapt to different shooters and even skill-level, as it is very popular it has a community around it that helps to improve the software with effective suggestions.
It costs $10 and gets on sale often, you can get it on Steam.
Another great way to train your aim, AimLab has a great way to show you your performance and more info on your aim. It has Overwatch on the list of games supported for sensitivity, so you can easily tune the cursor sensitivity to feel close to Overwatch.
The amount of customization in Aim Lab makes it great for Overwatch and it is also free on Steam!
Another option you can try, it gets compared to KovaaK 2.0 often but it became a matter of taste as both do the job. KovaaK 2.0 has more scenarios though, and you want an aim-trainer that is very customizable for Overwatch.
You can get Aimbeast on Steam for $6.
AimHero also can get sensibility settings very similar to Overwatch, it is a decent and straightforward aim trainer.
Currently available on Steam for $5 but also goes on sales often.
Are aim practicing software good?
This is a topic that you cannot be given a definitive answer to, it is something to try and see if you get better results from it. Aim trainers are widely used these days and you can see a lot of good players using them.
Finding a way to train your aim in-game is great, Overwatch is a game that you can somewhat practice decently on custom matches, sometimes you can see community custom matches open solely to practice aim, it is not as a big thing as Counter-Strike: Global Offensive custom matches but it's good enough.
The number of different scenarios and customizations that aim trainers have available is of great help to forget bad habits, as you can create a specialized scenario just to avoid repeating that habit or forcing you to stop doing it.
The bottom line is that techniques that work for someone may work or not for you, and the general sense is that aim trainers can help most people who put some time into it, but they're not a requirement for a good aim. Enjoy the process and aim for the head!