Note BillyHorrible's solution is more detailed and a better solution overall, however as i am transferring every solution from PlaystationTrophies .Org trying to populate TT with more solutions, I Found 4 potential Solutions to this trophy.
1) Start a game on Hard or Titan mode. This way, enemies take a few more hits to kill, thus making it easier to get this Trophy. In the first room, hit a couple of enemies with your Athena Blades then Spam Poseidon’s Rage ( + ) over and over again. You should do this 3 or 4 times overall and you’ll have your 500 hits Trophy. It’s that simple.
2) Other people have also suggested spamming Cronos' Rage in the room where you get it.
3) immediately after receiving the Atlas Quake from Atlas you'll temporarily have unlimited magic and have to destroy lots of enemies. Instead of using the Atlas Quake, change to Cronos' Rage and just spam it until you get above 500 hits.
4) Here's a surefire way to get this pretty early on in the game. Right after you get Typhon's Bane, there's a side room with a fire, some frozen chests, and four enemies that respawn infinitely until you melt the chests. They won't attack you if you stand just outside the room, and your magic refills automatically at this point. So just stand there and shoot them with the bow for as long as you want. You have to redirect your aim sometimes so you're not shooting the fire (this doesn't break your combo but doesn't add to it either). Takes a couple minutes to get up to 500, but very easy.
All credit goes to original authors at playstationtrophies.org, and this is merely updating truetrophy fans with these guides.
http://www.playstationtrophies.org/game/god-of-war-ii/trophy...