Something that I haven't seen mentioned is a book of gun laws pertaining to your particular state. As far as I know, there are books for just about every state that has most or all of that particular states gun laws, plus an easier to read and understand non-legalese explanation of the laws.
The Arizona Gun Owners Guide book helped me from getting in trouble. I had been under the impression that I could go onto school property (had to drop off and pick up my daughter from pre-school, located on a high school campus) with my gun as long as I had a permit. I could have it on in the car, but if I left the car I'd have to take it off and put it out of sight and lock the car. Well, after reading that I found out that the gun had to be unloaded prior to entering school property, regardless of anything else. If I had been caught, that little indiscretion could have been really bad for me.