What are the most important aspects of a club hitting a ball that have be taken into account?

Swing path and club face square to the line of the intended target. Make sure that your club face is actually aimed at the target by having a friend, preferably one you do not bet with, check it out. Practice lining up properly and then "all" you have to do is swing the club and have it come back to the same place it started. Practice by hitting 20-30 yard shots with quarter swings and make sure the ball is going where you aimed it. If the ball is not going at the target, you are not lined up properly of your swing path is not down the target line. Never hit a ball without selecting a specific target. Easy question to answer, but hard answer to learn.