I have played computer games since I was a kid, but I realize now at the age of 40, I am well beyond my prime. I get knocked down by kids in Overwatch all the time.
This is not a guide to how to become an awesome player, but rather a guide to those who are casual gamers who want to get better without too much practice and training.
A Simple Way to Aim More Accurately
I am terrible at aiming, judging just by how fast I can place my reticle on top of a stationary object. However I’ve noticed that a simple way to hit your opponent anyway is to utilize the fact that they move. Simply place your reticle ahead of their movement direction.
Now you have simplified your problem, to a timing problem. You just have to learn to react the moment your opponent moves into your reticle and fire.
This is what I do with characters that fire slot power shots like Ashe and McCree.
With characters firing lots of bullets, such as Soldier 76 and Bastion, I use a different tactic. I just get my reticle roughly where my opponent is and fire while strafing left and right quickly. Alternatively I move the gun back and forth quickly within a small area. That means even if you don’t hit with every bullet, some bullets will hit.
Use Clever Positioning to Avoid Need for Good Aiming
An alternative approach to learning how to aim well is to simply sidestep the whole problem. You can do that by focusing your playing style on placement. You learn the maps well and focus on ways of getting behind your opponents. Shooting people up close in the back, is a lot easier than shooting people actively trying to avoid you while firing in your direction.
Most levels are made such that you cannot easily outflank the enemy without getting discovered. The trick is usually to use various special abilities to get past areas where they can see our or shot you.
With Symetra I build teleporters to get me to difficult spots. Reaper can of course also utilize this trick. With Doomfist I use his rocket fist, to move forward quickly, as well as rising upper cut to get to high places. E.g. at the temple of Anubis, it is hard to sneak into the left entry way at the main archway leading to the enemy point, without getting shot to pieces by a Bastion or Orissa standing at high ground. But I can stand outside the line of fire on the right side of the archway and use my rocket punch, to move super fast towards the left side entrance. It is too fast for enemy players to hit me. Tracer can naturally use a similar strategy.
Sometimes it is just a question of being willing to spend some extra time moving into a strategic situation rather than rushing into action. I frequently get behind enemies with Bastion despite him being a big, slow and clunky character which has not special skills to get to tricky places. It is just a question of time. Once you get him in place it really pays off because in turret mode he can very quickly kill opponents. The downside with Bastion is that since he cannot move in turret mode, he is also very easy to hit. However if your opponents are facing the other direction they will usually not get the time to realize where they are getting hit or turn around before you have finished them all off.
Play Characters that Don’t Need to Aim
With some characters you don’t need to aim much at all. With e.g. Reinhard and Brigitte you are basically just clubbing down people anyway.
With these characters it is more about learning to use certain combinations of moves effectively. Brigitte and Reinhard are interesting comparisons. Reinhard’s shield can take a lot of damage but I feel pretty helpless when a Reaper comes charging towards me. I got one fire strike to lob against him, but I can easily miss. If I bring down my shield to engage him, he can start shooting me with some really pushing gunshots.
With Brigitte in contrast taking out a Reaper feels pretty easy. You just hold up the shield and he cannot close in on you like with Reinhard because you can use here shield bash to temporarily stun him. While stunned I work him over with my rocket flail while circling around him. That means he has to waste time turning around when he comes out of the stun, giving me extra time to hit him.
At that point his health may have gotten so low that Reaper tries to flee from you. Brigitte is not that fast, so often players can get away from you. But that is when you use your whip shot to catch them fleeing.
It is often like this with these melee characters. You need to use a combo of all their moves to bring down another character. E.g. with Doomfist you tend to strike opponents first with a rocket punch. It does not always finish them off and now you are quite vulnerable being a fairly big and slow target. So I follow up with a rising upper cut. But you got to be close to use it. While in the air, I finish with a seismic slam to either get the final blow or escape.