You are going to have to break things down into drills. During sparring you are reverting to old habits because you are under pressure, the answer is to drill some exchanges and gradually up the pressure. The skills you take from these drill should then carry into sparring and finally into fighting.
Lets take a left hook defense for example.
You get you partner to throw hooks. The first few maybe you just stand there and block. From there you can move round and he can hook to your head when he feels like it, using his foot work and body movement to try and hit you. Gradually up the tempo until he is trying to knock you out. Maybe do a round of this.
Do this sequence with all your hook defenses. Finally do a round using all you defenses. Repeat with all punches and kicks.
From here maybe do complex round (i.e he can jab, cross, low right kick). By this stage you should have a good carryover to sparring.
It's important that you partner makes this realistic and doesn't just turn into a left hook robot for a round, after all it's training for him too right?
Shadow boxing everyday will help, but will only take you so far. It is worth doing though even if is for a short 10 second bursts whenever you happen to think about it. Be careful where you do this ha ha.
Wear gloves for this!