1) Expect your kid will probably be the best thing to ever happen to you. The first three to six months will be trying but after than it gets exponentially more rewarding - there is nothing so simple yet pleasing as getting a big smile and hug from your little one. You'll have some occasional nights when you'll get no sleep, your kid will cry for hours, and you won't be able to figure out why or figure out a cure. It's going to happen, so just be patient with it because it will pass - think of it like an hour in the dentist's chair, not your favorite time but it will be over soon.
2) Take more pictures than you think you'll need, regularly back them up onto a big flash drive or portable hard drive (or get an online storage service) and keep them stored in a fireproof safe.
3) Keep an online journal and record all of those milestones and quirky, funny things that kids say and do the same day they occur - you'll never be able to remember more than half of them and will regret how much you forget in later years unless you record it somehow. An easy way to do this is just to keep it in one or two draft e-mails to yourself under a Hotmail, Yahoo mail, or G-Mail account and just keep saving it as a draft after every update. Here's a few examples from my journal of my daughter's quotes: [THUD!, from the bathroom] - Q: Are you alright in there? A: OWWWWW! I fell off the toilet and hit my head so hard I can't do math any more." [age 4]. Q: What's your favorite thing to do? A: I like to go hang gliding. I think I used to hang glide when I was two. I used to play tennis when I was a baby in my crib until I hit myself and cut my lip [age 3].