with a br of 150 you play 10nl (15buy ins) as you approach 375 try the odd 25nl table to get a feel for it when you know you are on your a-game (not when you just lost a buy in to a beat and want to get it back quicker!)
Otherwise you have to plug away against the morons (yes i play against them too!) until you are br'ed for a higher limit. Once you get into the 15buy ins for the next level you can begin to play at the higher limit on a few occasions but dont just move straight up.
Otherwise happy plugging.
(it will come if you play the odds and the numbers!)