I remember how cool it was when I figured out how to apply modes like Dorian, Mixolydian, and Lydian to my playing. All of a sudden I sounded a LOT better. If you’re pretty solid on the major scales, then I think you’re ready to tackle the modes.
There’s another lesson in the intermediate section) called A New View of the Modes. I suggest that you check this video out before watching that one. This one has a lot of guitar-specific info, while New View is a little more theory-intensive (and, it’s for all instruments, not just guitar.
Watch Modes for the Jazz Guitarist here