Improve is about feel . . . . I started learning to improv with just me and my guitar. I would start by playing a simple chord progression, slow with lots of space to "improv" (busy riffs will make it much harder to find your "groove"). Once the progression is smooth and established, start building lead "phrases". Use simple 3-5 note runs that you can fit between the chords and easily return to the rhythm on time to continue on. Build a lot of little phrases and learn to string them together into longer and longer solos. Remember to keep time and in the tonic of the rhythm your started.
As you get better you will find your phases or leads are getting longer and more intricate. You will also find that it is not necessary to jump back to the rhythm all that often as your solos will incorporate the rhythm seamlessly and the timing of the phrases is so dead on, they carry the weight of the tune.