Just a few suggestions from my experiences going solo.
Try to experience one of the very late EMH's, especially at MK. Even if you have to go back to your room and catch a little snooze after dinner. There's nothing as magical as MK at 2:00 or 3:00 am.
You can eat dinner at most of the restaurant bars. It's fun to chat with the bar staff and many times, others at the bar will chat to ask you how you like your food, etc.
A chair placed by the door to your room while you are sleeping will keep anybody from opening your room door without you hearing them. Also, be sure to use the extra security bar on your door, so you don't jump out of the shower and find the mousekeeper vacuuming your room!
Take lots of interesting pictures of architecture, gardens, whatever catches your eye. Nobody's going to complain that you are stopping to take
another picture!
On the topic of pictures, offer to take pictures of families with their cameras in ride lines, at restaurants, etc.
If you are interested in any of the tours, don't be afraid to try to get in at the last minute. The tours always limit their groups to even numbers and since you just need a reservation for one, your chances are better of scoring a spot.
http://www.wdwinfo.com/wdwinfo/tours.htm
Call 407-WDW-TOUR to reserve or for info.
So, just enjoy and know that you are much safer at WDW as a solo traveler than most anywhere else!