Good Thread! I'm pretty new at aquarium keeping. So far, so good.
What would I do differently?
1). Read more about what is required before starting. This forum is an excellent resource!
2). Set up a small (5 gallon) quarantine tank when your setting up your big aquarium. You'll save yourself a lot of worry and headaches about bringing in disease to your big tank.
3) Patience, patience, (and more patience)
Don't rush things. Don't try to find quick fixes for things as cycling your tank and stocking your tank right away.
4). RESEARCH YOUR TANK MATES! Don't just throw whatever fish look pretty at the pet store into your tank without doing your homework.
I'm sure there are a lot of other things I will discover as I go along, but for now, this is what I have learned.