Grip pressure is a killer in the golf swing. You will often see the knuckles going white as a person strangles the golf club. This tension prevents the hands from creating any sort of club head speed.
When you take a practice swing try to feel the weight of the club, if you can feel the weight of the club this will be the correct grip pressure. On a scale from 0-10, with 10 being very tight, grip the club at about 4.
You will often hear someone muttering "Stay down!" As you start the back swing the left shoulder starts turning. If the chin is tucked into the chest there will be no space for the left shoulder, this forces the shoulder into the side of the face and therefore the body moves up. This will lead to various compensations to get back into the correct positions, which will cause inconsistent shots.
Try and get your chin away from the chest. Almost get the feeling that you are looking down at the ball and not staring directly at it. This will improve your consistency.
A very common thought in the past was to keep the head dead still. Keeping the head still restricts a proper turn and weight transfer.
Modern day theory allows for a slight lateral movement on the back swing. The key in doing this is to make sure that the spine angle stays consistent and that you have good support in the lower body.
A very common fault is to aim incorrectly before putting the ball.
Even if you make a good stroke the ball may not go in the hole.
Fixing the problem is easy. Every golf ball has a logo. When you remark your ball get the logo pointing down the line of the putt. Get the logo lined up with the markings on the putter. This will ensure the correct aiming of the putter. All that you have to do now is to make a good stroke.
Do you often find that you hit a deep divot in the bunker, with the result being the ball staying in the bunker? If this is the case open your stance and your clubface. The sand wedge is designed to slide through the sand without digging in. If the clubface is open this will prevent the club from digging into the sand and therefore making it easier to get the ball out of the sand.