http://research.microsoft.com/mlp/trueskill/FAQ.aspx
jb
^^^I dont kno how dat helped but this is how it works (im pretty sure)
[u have to keep winning (as a team) and as u do, u will keep decreasing (<good thing) down in the LB. After u beat the lowest person on the next level u will increase and they will decrease one level. I decreased 1 level after not playin for a while, but i found it easy to go up since my postion (number) was close to the next levels highest person