The reservation lines don't open until 7:00AM ET. My friend called yesterday and was on hold for 30 mins. We got everything on our list but some of the times were not what we wanted. I think we were lucky considering we are a party of 9. We got Cinderella's Round Table
The problem I found is that on the first day you can make reservations you can make them for about the next ten days (I believe). That means others have had up to a 10 day head start on you. If you have trouble getting the day and time you want try for a day later in your stay.