Did you know the lock button on the side can work to either mute or lock the rotation? I'm not sure yet why I'd want to lock the rotation, though. Perhaps if something is viewed better in a certain orientation/layout? I also learned you can mute by just holding down the bottom volume key.
I am also learning about the multi-tasking bar. I have found this by accident on several occasions, but didn't realize how much easier it could make using my iPad.
I'm embarrassed to admit I haven't used the caps lock before. I didn't realise all I had to do was double-tap to get it.
One thing I am not embarrassed to admit I didn't know - when you're on a page which asks you to enter an email address, and the altered keyboard appears - if you tap and hold the period button, you'll get some autofills for the end of a typical email (.com, .edu, etc). I can't wait to try that!
That's all for now... let me know if you have any cool tips or tricks to share!