First, figure out how many days you will be in the Orlando area.
Next, decide what you will do with your time. Will you spend it all on Disney property, or do you want to see the greater Orlando area? (I'm one who is content to remain in the Disney cocoon -- I have nothing against the good people of central Florida, but I imagine they're just like me except that I own more sweaters and they know more about really big bugs)
Decide the above first, 'cause it can let you know if you think you'll need a rental car or not. If you're pretty much gonna stay within the WDW property, then there's no pressing need for a car. That can mean more money to have fun with!
Speaking of money, decide how much you want to spend on your room. Disney classifies three levels of resorts by price and amenities. Value resorts are the least expensive, have the smallest rooms, have the fewest amenities; they can average maybe $80 or $100 per night. Moderate resorts have slightly larger rooms and a few more amenities; they can average about $140-$170 per night. Deluxe resorts ... well, you get the general picture; they can average about $220-$600 or more per night. One extra amenity of all the deluxe resorts (except Animal Kingdom Lodge) is that they offer additional transportation options to the parks (over and above Disney Transport buses). Some are on the monorail, some are walking distance from a park, and some have boat transportation (and one of them, Contemporary, has all 3!)
Even if you stay at a WDW resort, if you have the time and money I strongly suggest you plan a day or two when you WON'T go to any of the theme parks, just so your BODY can rest and your mind can relax and you can just enjoy taking it easy on vacation.
If you are staying at a WDW resort and not renting a car, you can get a free bus ride between the airport and your resort, round trip. It's called DIsney's Magical Express; it also includes automatic luggage delivery to the inside of your room, which means you get to totally skip baggage claim. If you want private service and want to pamper yourself and pay for it, you can get an outside company to pick you up and drive you in a large sedan or SUV (but then you won't get the automatic luggage delivery).
Lots to think about. As you develop more questions, post them!