There is pretty good advice for beginners in the free 101 and 102 video series at crushonlineholdem.com imo. Basically, to beat 2NL you just play tighter than tight.

Keep reading the digest, read a lost of the posts started by Spoonitnow, post hands that gave you problems (with reads and ranges please!). Practice putting your opponents on ranges and calculating your pot odds, equity and EV.

A good book to get you started on the math is no limit theory and practice by Sklansky. This is important, because at the micros, the game is very mathematical.