I think also to avoid crashes more is to install the game to the HD, update the game, and have the disc buffed or with no scratches.

Act 2 When getting the trike vehicle do not boost off the first ramp when damaged. This made it crash for me for some reason twice in the same way.

At the end of the act wait a bit and not press A immediately to skip the cutscene. I think you're safe when you see Rourke and Zagato from above.

Act 4 Don't skip the final cutscene too fast.

Act 5 When at the final boss on the crate and you shoot the yellow thing holding it. Aim for the center of it and don't shoot too much. This causes the game to crash for some reason and don't use the machine gun. It's best to use the pistol to shoot it.

Also if you die sometimes it can crash so be wary of dying. This may be because of lag around you as this happened when I died because of exploding barrels. And another when I was in an area with some enemies and projectiles firing.