Watch the Changes: Solo online guitar lesson by Jeff McErlain from Blues-Rock Evolution

Playing jazz involves learning to outline the chords as you solo. This, in turn, requires knowing the names of the notes of each chord, their arpeggios, how the chords relate to each other and how to sound good playing over them.
Try learning one lick that works over a particular chord or chord change and practice the heck out of it. Use that lick as much as you can, to get it under your fingers. Then repeat. And repeat, and repeat...