Read carefully and apply and you're gonna get 10 more frags in every duel.
Your main weapons should be mg and rockets
Use rifle as some kind of extra tool but DO NOT, I repeat, DO NOT rely on it. You always use rifles in the worst situations, e.g. when your enemy has either more than 50hp or just 5hp and is jumping towards you.
You constantly get yourself into situations you don't wanna be in, the so-called "I gotta hit this rifle or I'm totally screwed because I gotta reload and even if I hit I'm not gonna get anything out of it" situation (patent pending).
Instead, use mg to finish off low opponents, and only use rifles when you can be certain to have a good opportunity to retreat and take cover in case you miss the rifle.
Also, a good rocket is like a fruit, it needs to ripen. Don't just fart out rocket after rocket, observe your opponent's moves and try to get a good prediction rocket out. One solid rocket hit is worth more than 2 bad ones. Same goes for mg. Try to actually aim and not just spray&pray.