Here's my list of Newbie advice (coming from a newbie):
1. Don't be stingy- spring the extra $$$ for the AP Freshwater Master Test Kit. Strips suck.
2. "The Cycle" - ask about it, read about it, study it, understand it!
3. A [acronym:c84d0aca1c="Partial water change"]PWC[/acronym:c84d0aca1c] NEVER hurts.
4. Do not mess with the pH - if its stable, leave it alone.
5. Be intimately familiar with your tank set up, bioload/livestock inventory, and water parameters at all times - you will be asked to recite them if you post a question on this site.
6. Never be afraid to ask a dumb question. When it comes to your fishies, there isn't one.