Okay, after being on this forum for a couple of days, I have realized that it's kinda dead.
Here are some ideas to promoting it.
1. Ads
This may cost some money, but it will make hundreds, and maybe thousands of more Ace Of Spades players, which they might go ahead and check out the forums.
Referral Contest
Have a contest on where whoever referrals the most people gets a prize, I don't know what.
Advertising
This may sound like spam, but going on popular "Facebook Game Pages" and advertising the game, and also advertising it on games like Minecraft or Steam.
Hopefully this helped!