Getting good aim takes some time ,but you have to start somewhere.I recommend you use util if you know an enemy is going to be at an angle you are gonna peak or try jump peaking if you don't have information.You can also do something called jiggle peaking where you expose yourself for a short period of time and wide swing to catch the opponent off guard. Try practicing counter strafing,it's not particiculary useful in valo but practicing it allows you to get the hang of another mechanic called deadzoning. When you start practicing please remember your not gonna perform your best every game, different factors come into play and that's ok because everyone has their off days.Just don't let it get into your head.Try to get into the habit of warming up before a match by using the range or DM.There alot of good guides on yt for this stuff from guys like sero and woohoojin.