The most important thing you can do is learn how to ride what you have. Don't go crazy doing a ton of mods. RIde it, learn what each mod does/effects the bike.
It is not uncommon to spank better/quicker bikes just because the rider had to have all the go-fast stuff his checkbook could get him, but failed to take the time to actaully LEARN how to get the most out of what he has.
If you take the time to learn how to ride/launch a short bike, you will be a better rider in the long run due to learning how to control the bike. Just my .02
It took me a good year of going 2 times a week and getting about 15-20 passes each night, and going through many stages of bike set-up before even touching the motor. Once I had learned how to get the most out of the bike, I started adding power. Results? Times started out at 10.9's with it in street trim, and the best pass I made was 9.23 with it modded. I can now ride my bone stock ZRX quicker than I could with my old one piped and jetted.
Hook up with someone that knows what he's doing and is willing to mentor you...I got lucky and had a few buddies that got me to where I am today.
Remember though...if you ain't having fun, it's time to give it up.