Watch the Improvisational Approach online guitar lesson by Jim Campilongo from Sonic Tele
Don't forget the basics! In your quest for new melodies and deeper expression, don't forget to ʺhearʺ in your head what you want to play before you play it on the guitar. Try to play an emotion, emulate one (or several) of your musical influences, sing your riff out loud and then try to play it or sing it while you are playing it. Ask yourself "what would I want to hear" as listener, then try to play it. There is no wrong or right way to go about this, but try to avoid "auto-pilot" riffing. The more your approach is in the now attained by listening and openness, the chances your playing will be more memorable and satisfying as an end result.