1st Step: Exercise your hand, This seems weird but it works. A way to exercise your thumb is to get an old mouse that you don't like anymore and click on it very long but of course you want to take out the chip and click on it everyday maybe 10 mins a day.
2nd step: Get a bow. No matter what get a bow and find a good camping and have plenty of arrows or infitnty 1 and shoot as many arrows as you can. To practice shoot arrows at target single-Player .
3rd Step: Corner them. Once you corner them they can't hit you as fast as you are hitting them and eventaully they will die
4th step: Use your Power ups when the battle starts. You should eat your Gapples, splash the potions and get the fight started. The reason why is because if you are really low and you haven't used any power ups you are more liekly to die.
5th step: Always fight the same number as the other team has. You should always have a 1v1 because if you are having a 5v1 you are gonna get hitten a lot times since there is a large amount of players fighting 1 player. Or someone on your team will get bored killing the other player and start killing your team.
6th step: Play Kit-PvP No soup servers. To practice your PvP skills Kit-PvP is the best since you get to fight any time you want if there is players online. The reason you don't use no Soup is because how likely are you gonna use soup while fighitng on servers not many servers have soup and most of them have soup.

If these helped please comment down below. 
Thanks for readin 
P.S: I'm making How to be an Epic Builder tommorow
And check out my projects on here http://www.planetminecraft.com/member/baconhd/

Have a nice day 
-Manliy