Just keep playing. Also it helps to have a good setup. IE fast computer, mechanical keyboard, gaming mouse. I assume you have those covered so I'll just say keep playing. I have a meh computer, meh keyboard and a gaming mouse coming. Still hold my own decently well.
Just gotta play and get used to the game. It definitely plays differently than console. Much faster. So you have less time to think and react. Also less AA so you gotta be better at tracking, but the stability on MnK is really nice and makes up for the lack of stickiness that controllers have.
Problems you'll face aren't the skill gap but the error codes and cheaters. The things that have kept me out of PC Trials and Comp. Why play and gamble with your sanity on not getting an error code or cheater. If you stick to 6s you'll thoroughly enjoy PvP on PC over console.