What makes a person better in ET.

So I was thinking to myself earlier, what makes a person alot better than the rest.
I mean for someone to be alot better than what they are now [ like me for one ] what is the best way to learn and progress?
Ofc learning to aim will help abit but there's so much to go through with ET, exploring each class and how they work properly and other nifty tricks, surely you'd have to learn some way or another but where, if most people you play with are still the same level.

Can anyone give some pointers here or links if this has been covered once -_-'

Thanks.