Visualize Your Putt
It's important to read your putt accurately and then visualize the path your ball will take as it travels to the hole. Get about 8 feet behind your putt and get as low as possible so you can study the break of the green. You are looking for creases and crevices in the green so you can see where your ball will break. If your putt is longer than 10 feet, walk the length of your putt so you can see every detail of the route your putt will travel.
Use Your Shoulders
Let your arms and shoulders swing the club while relaxing your hands. They'll do the fine tuning when it comes to the nuances of the putt and the breaks that it will take, but let your shoulders serve as the fulcrum of your swing. This is an important mental part of putting because your mind must coordinate the distinct jobs of your shoulders and and your hands.
Keep Your Head Down
This is essential with every shot in golf but it is perhaps most important in putting. You need to keep your head still in order to give yourself a chance to get your putt close. Do not move your head and certainly don't pick it up while you are in the middle of your stroke. You will not be successful in your effort to go from visualization to actually sinking the putt if your head is moving.