Hmm, well, if I was to recommend a starting point I'd probably take the old fashioned route and suggest the major scale and/or any of the minor scales, or pentatonic scales. Only thing I can really recommend with practicing scales is focus on one at a time and learn that scale everywhere on the neck. Find all the notes in that scale on the neck and practice them profusely. That being said, good luck to you and if I didn't spell something out well enough, speak up.