I got a 2003 warrior and i need some advice on what i should do to make it go faster.

 

When you say faster are you talking top speed?

Or faster when it comes to acceleration?

For top speed you need to change the gearing.

For acceleration the best start in upgrading a stock quad is
Full Exhaust system
K&N air filter with modded airbox
Jet Kit.
This is a good start in the modding game.

I'm thinking if you wanted more top speed you may need to pipe filter and jet it as well as change the gearing because it may not have enough power stock to go any faster.
This i'm not 100% sure on i have'nt spent much seat time on a warrior.