Right, that’s the three fundamental rules. You should probably have a quick thumb through the actual rules sometime. When you’re having a bout of insomnia is good!
There are a couple more things to mention:
Bloopers and Penalties
If you’ve infringed a rule, you can take a penalty and carry on racing: the penalty is two complete turns (usually called a ‘720’ or ‘720 degree turn’)
Or if you bump into a buoy, your penalty is a single complete turn (or ‘360’).
Penalties are supposed to be taken promptly (you shouldn’t wait till the end of the race and do them then!) and you should sail clear of other competitors before doing your turns.
Those were rule 44 (720°) and 31 (360° turn) of the Racing Rules of Sailing.
The last thing to mention (but not the least important!): keep a good look-out! Behind the mainsail. Under the jib. Close-quarters situations develop fast and the earlier you spot them coming the longer you’ve got to consider who’s got right of way and how you need to react.