Training for defensive shooting is NOT like target shooting, targets do not shoot back. Learn to shoot at closer ranges with BOTH eyes open - come to a class and find out why! Also learn to shoot on the move (safely) because you will likely need to be moving to cover as you defend yourself.
Own a lot of guns?
My dad used to tell me "beware of the one-gun man." His point was well taken; generaly speaking someone who depends on one gun may very well be very good with it!
How many different carry guns do you have? For me, the weather plays a role in what I carry but the key is, I PRACTICE with what I carry. My advice to a lot of people is 'limit' the number carry guns you use or at least stay with the same "operating system" or brand since they will function similarly.
This may seem off subject but stay with me. I ask a lot of people if they have ever tried to shoot in competition. Generally the answers are; "no, I'd be too nervous" or "I'm not good enough." Then I follow up - do you carry? Answer; "you bet, all the time." Do you see a potential problem here? If you ever have to use your gun in a defensive action, do you think you will be nervous, scared, or what if you are already injured? Will your fear and adrenaline undo everthing you ever expected would happen when that time came? Shooting with a timer or in competition, or even a friendly pratctice shoot with others really helps take that anxiety level down.
Practice does not make perfect. Practice just reinforces what ever skill level you have attained, and for a lot of people that is not very high. Perfect practice makes perfect. Or better yet, good training makes you better.
Re-assess what you carry, how you carry it and ask yourself, if I need to use my gun in the next 2.3 seconds - am I ready?