Every player who has a facebook account should join the battlemaster account there, and Like every post Azerax makes in the group. This kind of thing gets battlemaster more notice on facebook, and can he'll it google ranking.
Since player retention is a problem, it ought to be solved first. With a retention problem, you are bound to lose a large portion of whoever you succeed in advertising to, so that leaves little reason to advertise in the first place. What is at the root of the retention problem? Looking at whatever statistics you happen to have would tell you a lot. Determine points in time in which retention was high and then look at what in-game circumstances were like at that time.
The same method could be employed in figuring out the ideal way to gain players. Determine when player build up was at it's highest, then look at what was going on at that time.
This isn't a perfect method. It doesn't take external circumstances into account. But it's a good starting point for developing a strategy for dealing with those problems.
