Here's is the most important advice anyone can give you... Find a guitar mate that's better than you. Most people find teachers, some ask friends or parents.
What you need (expecially if your rhythm sucks) is someone else's ears and sense of rhythm.
Work on songs you love, any style. You mate will tell you if a song you have chosen is easy enough...
TAB books and sites are a great way to document oneself, but NOTHING compares to someone that will tell you 'you play too fast' and that taps his foot to tell you how to get in the pocket...