It's pretty simple.
Since the time that CounterStrike EXP was lowered on garena.com, the only good alternatives are:
a) playing COD4
b) Playing a WARCRAFT (the Frozen throne) custom map called Fufu United Ninja AllStars
all you need is to host the game with 12 players and click 50 kills
Games finish around 6-7 minutes, repeat process for as much as you want
See your EXP boost like crazy
Tried and tested
Proven by a lot of level 50 accounts
Download the map at www.getfufu.co.nr or www.fufuportal.blogspot.com
More mirrors at:
If you have more tips and tricks, feel free to comment.