It's not hard to rankup from gn to mg.

you just need perfect timing and it would only come with experience but you can do 1 more thing.

MOVEMENT

yeah movement make you more perfect , you just have to fight with 1 angle . try not to come in front of two enemy coz you cant handle that

so what you have to do is download YPRAC workshop and start practice in prefire and follow the given line.

prefire practice would improve your game so much and you can easily rankup to mg .

good luck