Your room key will move you up on the list.
Rush hour at the restaurants is 8pm, especially Margaritaville. We showed up at 8pm and they gave us a beeper. The wait was 20 minutes. They told anyone else who walked up the wait would be 1 hour. We walked around Citywalk taking pictures and 20 minutes later the beeper went off and we got a table. The place was packed at this time with stilt walkers going thru the crowd, it felt like a giant party. When the volcano went off, everyone cheered and sang along to Margaritaville "Salt, Salt, Salt."
If you want no wait and things a little more quiet, then go earlier at 05:30pm.