Try doing defensive techniques when shadow boxing?? Act like you're fighting another guy in real life. Parry, cover up, duck , bob and weave, slip, move your head, etc.
Run a rope from one side of the room to the other(shoulder level). Bob and weave up and under the rope to get better. You can also incoporate jabs, crosses, hooks, uppercuts, and multiple combos when you come up.
If you have a hanging bag, give it a light swing and work on moving around it. Keep the bag moving as if its the opponent moving in or around you. This helps your footwork to achieve better defensive skills. Benny "The Jet" Urquidez did this. It's a very good technique.
