its hard to really give any advice on this one. I played SM2 for 100's of hours in total- I could literally land exactly where I wanted to at high speed and I beat all of the "trick" missions- including the hardest ones.
But the arena....well, what can I say? swing to avoid projectiles and try and get as many villains at once. dont concentrate on anyone baddie if hes giving you the run around.
I cant remember the button sequence but the move where spidey web yanks, flips back and does this long-range kick is the best way to get multiple enemies. (I think its triangle+back,sq, tri, sq.) does a lot of damage too.
use as much spidey sense as you can. swinging cannonball kicks are great as well. dont forget you can web yank enemies whilst youre mid-swing.....
then you can take advantage of the high celing by dropping them with the "twisting head smash"/piledriver- you press a button repeatedly to get more rotations.
web yanks whilst swinging is a good way to get the guys to fall over- then hit them with the long-range kick
just keep on using the webs so the enemies dont get too far. dont miss any counter opportunities either. use the launch combo only after you dodge
you probably know this already though, best I can offer. there isnt really one strategy. web-zip to get around- you dont have time to run-plus it gives you a chance to start a combo on a bad guys head. if you web zip toward him