A few suggestions for newbies like me:
1. Ask reliable sources who've made the trip for their insight: it could be invaluable.
2. Join AAA if you haven't already: if you are driving at all, they will make it so easy for you to get where you need to go.
3. If you are thinking of visiting other attractions, look into CostCo.com's Southern California CityPass and consider the difference in price of this pass (which includes Disneyland (3 Day ParkHopper Pass, w/ one early admission), Universal Studios, The San Diego Zoo or Wild Animal Park, and Sea World) versus the price you'd pay to go to all of those things individually and NOT get into Disneyland an hour before it opens to the public.
4. Last, and most important, go to a site called MouseSavers.com. Holy cow, does this person know what they are doing when it comes to all things Disney! It's truly amazing how this site pays close attention to detail, offering you all of the ins and outs of all of the Disney parks, right down to the amount of money you could save w/ your AAA card at various food stands (and, hey, Kids Eat Free at the IHOP across the street from Disneyland gates after 4pm!).