How do I get better at CS:GO?

Oh yes, something that I forgot to mention, there's a ton of Aim maps, and Smoke maps, and Flash maps and things of that kind that'll help you fine-tune those smaller and important skills.
If you use them correctly and practice on them often you'll be able to prefire corners and smoke things like a professional.
Once you have that down, you're going to be a really good addition to any team.

-Though I'd mention that you should only really do these kinds of things once you've at least tried to master some of the basic weapons, otherwise these would be kind of pointless.