Bradford Werner points out that having musical friends is just as important as practicing. I agree. Most college guitar programs make use of the first benefit of having musical friends: a low-stress environment where people can perform for each other. Having a regular performance opportunity will make you a better player. There are quite a few other benefits that Bradford outlines as well, and he gives a brief list of places where one can make musical friends.
Nick Cutroneo wrote a very brief, insightful post on the ways the left hand thumb can help navigate the fretboard. I use a lot of the second method: allowing the thumb to move vertically.
Lastly, you can check out an in progress guitar over on the GSI blog.