Practice, Practice, Practice is all it takes. It also helps if you want to get better online is to play people that are much better than you. Learn from what they do. Although it must be noted that a small or large (Depending on your views) part of Gaming Skill is natural talent. Hand Eye Coordination, Reaction Time, Reflexes and Split Second Decision Making are all key factors.
Talent I haz non.

Hmmm, I like pretty graphics and mash buttons fairly slowly but I make up for it by being inconsistent. The only time I quit is when I'm in a public match and I get a game invite from a friend. But only if it's early in the match or if I am not doing exceptionally well.