A note on practicing scales.

It is more important when practicing scales to develop an ear by playing them around chords than it is to simply do wrote, technical practice of the scales by themselves. Try playing a chord and then playing the accompanying scale for that chord and you will notice how the G major scale for instance sounds if you play it directly after strumming a G major chord. You can also try playing a g minor scale over the G major chord or try playing a g minor scale over the G minor chord for that matter. Definitely play the G minor scale after strumming the G minor chord.

In this way you will learn to understand how the scales fit with the chords and how the sounds work together which is much better practice than simply running through scale diagrams although there is a place for that as well. Running through scale diagrams will increase your dexterity and comfort level with the guitar and also give you practice with alternate picking.

http://musicouch.com/music-making/guitar-lesson-three-open-chords-bar-chords-and-some-scales/

http://musicouch.com/instruments/string/guitar/guitar-lesson-two-the-g-major-chord-scale-and-more/