Start with
this. This is the Secrets prefpane and it will let you adjust a lot of hidden settings for both OS X and a lot of the native apps. I am suggesting starting there because I could rattle off a few things that take a couple of different apps to take care of (Onyx, TinkerTool, etc). This is just easier.
- Go through it. Find anything that relates to animations and shut it off.
- Use ShadowKiller to kill window shadows
- Turn off Icon Previews on your icons
- Avoid using coverflow view
Extreme options:
-Turn off Spotlight
-Turn off virtual memory.
Secrets should cover a lot of it for you. Be careful though.