The best way I know is to watch a lot of John Wayne, Clint Eastwood, and other western movies, paying particular attention to the gunfight scenes and fight scenes, and watching other action movies can help, but Westerns generally focus more on the gun fights. (This is a joke, but it can help).
Aiming:
Just look down the barrel, if it's an intruder in your house, most chances it will be to dark to see the sights. So just learn to look down the barrel, and point and shoot. After practicing this, it should become second nature which way to hold your hand to hit the mark. It's best to get to the point that you don't have to see the gun to know where it's pointing. Because turning on the lights in an intruder situation will momentarily blind you, it's best to leave them off, and you should still be able to see the intruder.
Fast Draw:
I've shot pistols for years, the best way I've found is to file off the front site, so it will clear the holster on a fast draw, and look down the barrel at your target. Start by slowly drawing the pistol up out of the holster, looking at your target the entire time, and keeping the pistol moving straight up. Practice this with tall straight trees. Do this many times with an unloaded pistol. Then start practicing pulling the hammer back as you pull it up, keeping the pistol moving straight up, and then pulling the trigger when the pistol is straight out from the body, always facing the target. After a week or two with this, do it with a loaded pistol, firing it like this. Also, it is good to see if you are hitting your target, if not, see at which angle your body needs to be to be looking down the barrel from a straight draw. Just pay attention to following it very closely, and practising. And always keep both eyes open, you can see your target(s) better this way. When you get all of this down, and you can draw and fire and hit the mark well, then you have it. The more you practice, the faster you will get.