What are the "sure" methods of reducing windows startup time?

My bootup speed is annoyingly slow. I know there are a few tips n tricks for reducing the time it takes to reach the desktop from the initial power on.

But what are the most effective of these tricks or hacks?

My details:
Windows XP Home running on a 256RAM, 2.5Ghz P4 laptop (with wireless internet). The computer is used mostly for surfing and P2P.