Keep it in the fingers
One of the biggest faults I see in amateur golfers is a grip that sits too much in the palm of the left hand, so much so that sometimes a hole is worn in the heel pad of your glove. Placing the club more in the fingers can help relieve tension in your swing, allow you to hinge your wrists correctly and help prevent a number of other swing faults. By starting with the club in the air out in front of you it becomes easier to position the clubs correctly in the hands.
Stance and posture
Don't make the mistake of thinking that stance and posture is merely making sure your feet are aligned correctly to the target and your knees are bent. Whilst this is a factor, a proper stance should enable you to be perfectly balanced and poised throughout the swing. Without the correct stance and posture it becomes harder for your legs, arms and body to move correctly.
Keep your ball position consistent
Ensuring the ball is placed in the correct position can often be the cure for poor ball striking. It is important to remember that as the club gets longer you need to stand further from the ball, increase the stance width and move the ball further forward in the stance.
Be in control
At the foundation of every good golf swing is good balance. Maintain your balance and you can deliver the club to the ball with speed and accuracy, lose your balance and the chances of getting a good connection is greatly decreased. A fault I see all too often is a player having too much weight on their back foot at impact, often resulting in fat, thin or weak shots. This is caused by poor weight transfer from the back foot to the front foot during the downswing. I like players to feel that once they have hit the ball, they finish with their chest facing towards the target, the majority of weight on their front foot and their their back foot turned on its toes.
Find your tempo
Everyone's golf swing rhythm and tempo will move at a different beat. Some golf swings are faster than others but this doesn't necessarily mean they have a poor rhythm. Your tempo can be likened to the way you walk, if you are a fast walker you are more likely to have a faster golf swing. If you are slow and deliberate, chances are you will be more suited to a slower, more deliberate swing. The important thing is to find a rhythm that works for you and stick to it.