In addition to the good advice above, I recommend that you take a look at a list of Massad Ayoob's books and select a few related to combat situations and preparedness.
I don't think the area of mental preparation gets enough emphasis...seems like most of the attention is directed to the techniques of shooting and putting holes in paper. I don't think this can be minimized at all, but there is another important element too...it's right between our ears, and most of us don't know how that thing we call our brain will react in a bad situation. I go to the range regularly, and would like to think I'm a decent shot. The question is, would I also be ready in an adrenaline-pumping situation?
I couple of years ago I pulled up behind a Geo Tracker that was on fire...all of the flames were shooting out from under the hood, and it wasn't going to be long before the whole thing went up. Anyway, I quickly got out to retrieve my fire extinguisher from of my truck's toolbox (it uses the same key as the ignition). It was almost like a dream, as the adrenaline pumped away. My hands were shaking as I fumbled with the key, forcing it into the lock. I eventually got it open, and with the help of another passer-by, put out the fire. I ended up bending the key badly and almost messed up the lock. Know what that taught me? I was mentally unprepared for the adrenaline. If I would have calmed down, thought methodically, and maintained a clear head, I would have gotten the fire extinguisher out quicker AND not messed up my key. I learned a lot that day about the effect of the brain on the body. And in this case, I wasn't even in danger (well, some, but you get the idea)! Now, translate this to a situation where I draw my weapon and I'm so rattled I can't find the safety! It wouldn't matter if I'm the best shooter in the world, I would lose!
To sum it all up, you need the 360 approach. Go to the range, become a good shot, work on your techniques, but also get the mind prepared for anything. This way, if anything unfortunate happens, you'll be prepared inside and out, and you won't "bend your key in the lock". Ayoob has written many books that will address both sides of the preparedness equation.
