One quick explanation for melee, i belive it has been said before, but ill say it again just cuz i can :
TO MELEE :
1. Target someone. (Click once while there under ur aimer)
2. Swoop at this person. (Click again.)
*Note* So to swoop at someone quickly, double click.
3. HOLD Secondary Fire. (default mouse2 [right click])
If the person didnt see you coming, or dosnt block, or dosnt swoop at you, they go flying in 1 of three directions. Up, down, Straight, depending on the angle at which you nail the bugger!
Holding the secondary attack while meleeing is crutial if you ask me, because its alot easier than clicking constantly, and you will have the button down once your in range to attack, instead of having to time it.
Also, if your going to melee someone, and he is coming at you, and your going at him, and you constantly get hit back... Then simply use that thing between your shoulders. Your Head. Try stopping short and blocking at the last second. Or veer to the left/right and attack from the side. Or stop, And teleport behind the guy, swoop again and send him into a world of hurt.
*note* To stop short in a swoop, left click again.
This is a very basic stratigy. I would think you should come up with your own style of melee.
*NOTE* I find vegeta best for meleeing. If i use other characters, i tend to start using there beams. But if u want hardcore melee, use vegeta becuase his beam sucks ass until he hits SSJ, Then he just rocks everyone.