There are several little things you can do to get a head start with the expansion:
  • Leves - Accept 16 different leves. This lets you get beyond the limit of 100. Complete up to turn in for DoW/DoM, and don't forget GC leves.
  • Beast tribe quests - Accept six before the servers go down and complete them up to turn in. Turn them in at patch and get 6 more before the daily reset.
  • Challenge Log - Don't complete anything that gives exp before early access. Complete 2 roulettes and 2 additional dungeons, giving out commendations on all, then do a roulette during early access, give that 5th commendation, and boom 35% of a level exp. Likewise do 9 FATEs in 4 different zones, and first FATE in new zone gives a bonus 30% of level.

Feel free to add any more tips.