Well first off, the chords you know... Most of those aren't in modern songs. Ask your teacher to show you power chords and a few lead scales. Have him show you how to pick using up and down strokes, how to string bend, slurs, and other techniques. Have him also show you how to read tablature, this will improve your technique the quickest and you will see how modern songs are put together. And if your teacher doesn't know how to play rock music find another teacher. Also don't be afraid to ask your more advanced friend to show you a few things. Hope this helps out.