Tips that will improve your putting stroke
Target line. Align the sweet spot on the putter blade exactly along the target line. Most putters have a target line inscribed on the top of the blade or on the flange behind the blade. Place the putter so that this line points to dead center of the ball and straight through along the target line. This is the exact position you want the putter blade as it strikes the ball.
Eye on the golf ball. When you are in your putting stance you do not have to look straight down at the ball. Phil Mickelson thinks he can aim the ball down the target line better if the ball is a couple of inches forward of center in his stance and a couple of inches forward of a straight-down look at the ball. This give him a view down the target line that is from slightly behind the ball -- he has a better view of both the ball and the target line.
Putter style. The style of your putter affects the putting stroke. A simple blade putter with the hosel (where the shaft connects with the blade) in the heel of the blade tends to move in a slight arc; e.g., as your begin your backswing the blade naturally rotates inside the target line. Your downswing brings the blade down along this arc, striking the ball exactly on line at impact, and then arc inside the target line during follow-through.The key is to consistently strike the ball exactly on line. This take practice.
The alternative is to try and force the blade to remain exactly on line during the backswing and downswing, therefore striking the ball exactly on line. This is a bit unnatural -- you must rotate your hands a bit to maintain the on-target alignment. This goes against the principle that your hands should serve only to connect your arms with the putter shaft.
Force of putting stroke. For a short putt requiring a soft putting touch with little forward force, the backswing should be short. After striking the ball your follow-through should be twice as long as your backswing -- extending your arms and putter along the target line, For a longer putt use a longer backswing and longer follow-through -- try to keep the rhythm and feel of the swing the same as for the short putt. Longer distance results from the longer backswing. Work on your putting stroke and you will gain confidence in consistently making those short putts.