This is something that has always bugged me. I've always felt I needed something to just practice instead of just playing songs. Last night I found this link on Pebber Browns website. Gives a lot of good tips on what you should be practicing. A lot of it is just the basics, but that's what it takes to get good. I suggest watching the video and following along as best you can. It's boring but you'll get the idea of what hes trying to teach you as far as practicing goes.

Putting this in another similar thread as well.

Daily Practice routine:
http://www.pbguitarstudio.com/DailyPractice.html