1) When looting, prioritise bigger magazines.
2) Hit your target.
3) Hit your target's head.
With specific regard to the Peacekeeper; be wary of enemies close up who have one.
Especially if they have a choke (you'll hear it charging/charged up), as it drastically reduces the spread making maximum damage hits (110 body/165 head) more likely.
As to how to improve your aim:
- Record yourself playing.
- Watch back your recordings, to see how well you actually aim.
- Compare your aim to other players, such as streamers.
- Practice!
On the flip-side, learn to make yourself harder to hit.
- Don't stand in the open
- Don't stand in predictable places
- Don't stand still
- Don't move predictably
- (almost) always make sure you have the high ground.
- Jump!
- Crouch!
- Jump and crouch!
- Don't let your enemy anticipate your next move, anticipate theirs instead.
- Head-on 'fair' fights are for chumps; you want to be attacking from where they're not expecting you.
Getting the drop on an enemy is how you kill them before they kill you. It also minimises your damage taken, so you're more prepared for the inevitable 3rd parties.
- Don't sit cowering around corners.
Due to the way Apex Legend's net code works, the person walking around the corner into your field of view has ~500ms to attack you before you're able to react. Instead, always stay moving, ideally being the aggressor.
Other things that significantly help:
Get a high refresh rate monitor (144hz, 1ms response time).
Make sure your pc is fast enough (or detail settings low enough) to hit 100+ fps when it matters.
Beyond the things that directly help you to personally deal more damage:
- Analyse each time your squad is wiped, and think about what went wrong. What decision(s) leading up to your defeat was/were a mistake(s)?
- Communicate with your team mates (both verbally, and with pings)
- Make sure you have team mates who communicate with you.
Having (and being a) good team mates who call out the locations of enemies is critical to situational awareness, and help avoid those bad decisions that lead you to a defeat.
Likewise, having a cohesive team who are communicating. and positioning themselves to support you and distract enemies, makes the shooting aspect many times easier.
e.g. It's easy to kill someone before they kill you, if they're unaware of you, and are instead chasing your team mate.
There are certainly players out there who rely upon their godly aim and insane reaction times as a crutch to do well, but they're a minuscule minority.
There are far more players who have only good aim, and instead compete with smart play & strong team play.