It can be very difficult to unlock the 1000-hit combo trophy in God of War: Ascension naturally. As you get better at the combat system and replay the story, you'll probably get closer and closer to it, but if frustration is keeping you from sticking with the challenge. Here are two incredibly easy ways of unlocking the trophy.
This first method comes requires the L1 + Square Lighting attack. You'll use this method in Chapter 19 in the Foot of Apollo.
The second method occurs much earlier in the game, in Chapter 5. This is right after obtain Ares Fire. Do not press L3 and R3 as the rage meter insists. Instead, just keep grab and slamming this enemy to continuously juggle until you've racked up enough hits for the trophy.
Neither of these methods are pretty and both will take some time, but make sure you get the trophy the easy way before the exploits are patched out!