Make a daily quest to queue up for /cbattle. The reward should be mouth watering enough for all players to want. I imagine peoples faces going from o_o this, to this when being told about the quest reward. This will increase number of participants as well as get the ball rolling for some less experienced players. Note that players should not be encouraged to queue up and subsequently and immediately leave queue and/or Run from the battle with this quest
Great idea, i also thought of that as a reward because it would help players gain more access to competitive items. Another prize suggestion would be a lucky egg or a new item that gives raw pokemon EXP. This helps pokemon reach a competitive level sooner. I want more prizes that motivate the common player to queue up for /cbattle confidently. Above all i want more players to queue up even if its with non-competitive pokemon.