My post #8 went on a bit long and recommended some pretty thorough training. Let me qualify it a bit.
Most experienced clerks in dedicated gun stores are able to show how to disassemble and reassemble their inventory for cleaning, and perhaps even some maintenance. You may not need a specialized class. Many guns are sold with adequate owner's manuals from which, with some work on your part, teach you how to maintain your gun(s).
The NRA has some excellent resources for studying up on safe gun handling. How well you incorporate those habits into your life is up to you.
There are some good books on shooting techniques all over. Also shooting tactics. Books like In Gravest Extreme, No Second Place Winner and the like. Also web sites like CorneredCat.com.
Learn all you can. And continue to learn.