2. Hitting what you're aiming at.
3. To use both hands while firing.
Keep in mind that when the second amendment refers to "a well-regulated militia" it means "a group of citizens formed to defend its community" not "the United States military." This is confirmed by the fact that the second part of the second amendment begins "the right of the people..." not "the right of the military!"
Furthermore, Federal gun control laws are inherently unconstitutional because they violate a state's rights. Remember the Tenth Amendment? The Federal government does not!
Of course, I will not attempt to argue with you gun control advocates who disagree with the facts. Your disregard for reason and factual information is enough of an argument against you. While you cannot help forming an opinion, that does not mean your opinion is right.
2. Applying proper use to a firearm, as to be able to accurately accquire and dispatch hostile targets.