First off, congrats on your purchase, new cars are fun! and these are wonderful cars.
But, there is a tremendous amount of info on this board, and others on the net as well. Rather than say "What do I need to know?" and expect quality answers, take the time to actually read through whats out there.
If you bought a car blind, now is your chance to make up for it and read. Its really the best way to learn. I've had mine for 4 years and 80,000 miles (for a total of almost 130,000) and I was on this board and another bimmer site for a year reading and learning, and based my buy on what I learned. Hell I had an exhaust picked out before I even bought the thing
Not trying to sound like a dick, but put in a little effort and you will be rewarded.