This had been my first season of racing, and I've learnt a lot just in the 5 races I've competed in. Few bits of advice I've picked up:
Get a real good base fitness going, there's no substitute for miles on the bike, hour after hour, mile after mile, it needs doing.
Become a skilful rider. By this I mean become really agile, nimble, feeling in total control when crowded with others around you. Learn to read what's happening around you so it becomes second nature.
Train using big efforts followed by recovery, rinse and repeat. Train until it hurts. If it hurts it's doing some good. If it doesn't hurt, work harder. Always follow a hurt session with some good quality rest.
If you can afford one, buy a power meter. This will not make you faster in itself, but by learning how to use it properly will give you fantastic knowledge of yourself and what you are/could be capable of.
The most powerful rider will not always win. There is a super strong muscle between your ears, use it well and race smart.