The usual advice to noobs is to "just do it" al a Nike. That's pretty good advice. That feedback is very direct.
If it is possible do training rides with people that actually race, like mentioned in botto's sticky. Some of the ride might actually be similar to racing (usually the town/county line sprints). If you show any talent they will let you know. If you are a total squirrel the will "yell" at you.