What should I know before I start entering races?
I've been cycling for one year now after an injury ended my running career so I'm still pretty much a beginner. I'd like to try my hand at racing but I've noticed there is quite a lot of etiquette around cycling so I don't just want to roll up to the start line and anger all the other competitors.
Contact a local club.
Most have regular training outings (weekends, evenings), you'll meet other racers who'll willingly teach you the tricks of the trades, the local routes and just the espirit de corps which makes competing all the better. (As well as recommending the best local events.)
Everyone was a beginner once, although not everyone remembers that. If there are no online chat rooms for clubs in your area it might just be worth going out cycling in the local area of a weekend morning and trying to see groups in similar kit and just asking people. Especially if you can find where they stop for tea!
As far as what you should know--the most important thing from a safety point of view is to have some experience (and comfort) with riding at speed in a pack.
As already mentioned by Unsliced, club rides (and, if you can find them, training races) are great places to learn.
