1. Read the manual
2. Read other books
3. Practice
Many buy these fancy cameras and keep them on full auto or at best P mode. They don't understand exposure, ISO, shutter speed, F Stops, Depth of field, composition, or really anything about photography. All their photos look like snapshots and could just as well be taken with a camera phone. If you spend the time learning the basics and then practice you'll be way ahead of the game.
I personally bought a book specifically for my camera. Not one of the dummies ones but something basic along those lines. I read that along side my manual and I read them more than once. I then picked up some other books explaining exposure. The first one I read wasn't even with respect to digital but explained Ansel Adams' zone system which I found interesting. Other books worth noting would be post processing books such as the ones by Scott Kelby. There's quite a bit on the internet as well. Google "exposure" or "perfect exposure".
Also, don't buy a whole bunch of lenses when you start out. You should buy one and then when you understand what you're doing you'll know which other ones to get.