Check out the four basic safety rules from the Armed Defense Training Association.
Article credits: http://armeddefense.org/safetyrules
The Four Basic Principles of Safe Gun Handling
To help ensure safe practices at home and on the range, make these gun handling principles your own, and they will become natural habits whenever you handle a firearm. The Armed Defense Training Association (ADTA) observes and enforces these principles at all ADTA events, from demonstrations to dry practice events to live fire events, and we're glad to help new shooters get started.
1. Treat every firearm as if it's loaded.
Even if you're absolutely certain a gun is unloaded, still follow these rules for safe gun handling. You want these rules to be natural habits; holding yourself to them each and every time helps make them so.
2. Never point a firearm at anything you are not willing to destroy.
Accept the mindset to always keep your gun pointed in a direction that would safely stop the bullet should it discharge. At an ADTA event, if you're not on the firing line, your gun should stay holstered muzzle-down, cased, or locked open and pointing down and away from people. If you're on the firing line, your gun should stay pointed downrange, at the bullet trap backstop at the end of the range. If you will be cleaning or handling your unloaded gun at home, find a safe direction ahead of time -- bullets penetrate floors, ceiling, windows, and walls. Masonry, a full bookcase, a full freezer, downward (if you're on the ground floor), or even a five gallon bucket of sand may be good options.
3. Always be sure of your target and what is beyond it.
You are responsible for the entire path of every bullet you fire from your gun. If you hit your intended target, the bullet may still continue through. ADTA live-fire events are conducted at locations with designated bullet trap backstops or berms to help contain rounds to the intended range area; you are responsible for only aiming in directions where you can be assured the bullet will be safely stopped.
4. Keep your finger off the trigger until you are on target and ready to fire.
At ADTA events, when you're holding a gun but not shooting, you'll hear us ask you to "index" your trigger finger. This means to keep your trigger finger straight, and to raise it up to rest flat alongside the body of your gun. Whenever you are not on target and ready to fire, your trigger finger should always be outside the trigger guard and resting straight and flat alongside the body of your gun.