Firstly if you have not done so already then visit the Halls of the Novice and do the introductory "duty" there, you will be rewarded on the final duty with a ring that gives you 30% additional exp on DoW and DoM up to level 30 so it is really, really worth it.

Then you have your hunting log which pulls in lots of extra exp, plus Fates, Dungeons and Leves (unless you want to use them for other things). I appreciate that the times you are on may not be great for fates or dungeons and your guild is also quiet. It may be time to consider using a server transfer to one that is more active when you are online?