I think reading music is important. It will teach you not only to read music but also a lot about timing. Like Metalmanbc said, tabs won't teach you timing, only notes.

Also, I found that playing with a good midi file in the background is great for improv and timing. If you're like me with nobody to practice with, you can get descent improv exercise with a midi file. Most are free on the net so it's not too rough on the wallet. I'm a big fan of free stuff :).

Try to lay some of your tricks and licks on the track.

Just try out some different styles of midi files, blues, jazz, rock.

Hope this helps.