It seems a lot of players are stuck at 2NL. I've seen players blame Renton's guide to beating 2NL.

Seriously, what is said in the first post in this thread by m2m is all you need to know to get out of 2NL, 5NL, and maybe even 10NL.

Stop bluffing. Stop worrying about 3betting lightly. Stop worrying about balancing.

Just value bet.