Most putting tips that you will find in golf books or online concentrate on improving your aim. This is not the only thing that you can do to boost your putting technique, but of course accuracy is important.
The best way to increase the accuracy of your aim is to improve the contact between the putter head and the ball, so that it is straight and you are using the right area of the putter head. If you are constantly compensating for a tendency to hit the ball slightly off, this makes every putt a hit-and-miss affair.
Something that you can do when practicing (and even in a match, under most rules) is to draw two parallel lines on the ball with about a half inch between them, and corresponding lines on your putter. Practice until you can hit the ball so that the lines exactly meet, every time. You are pretty sure to find that this increases the accuracy of your putts, and when it has become natural you can stop drawing the lines with equal success.
It is often worth trying a new putter. Even if you are very happy with your current club you could maybe borrow or rent a couple of different ones and try them out. If you have had yours for a long time, your game has probably changed and another type of putter could be better for you now. Give them try before deciding whether to stand or switch.
Most professionals advise taking a bold approach to putting, and shoot strongly. Even on a fast smooth green you should not make your shot too soft. Generally it is better to send the ball past the hole than to stop before it.
Keep in mind that if your putt is accurate, but not strong enough, it will always miss the hole. But if your putt is accurate and too strong, it will probably go in. Dave Pelz (aka Professor Putt) used a robot to carry out a study that proved that the best putts were strong enough to have carried the ball as far as 17 inches beyond the hole, if they had not been sunk.
A strong putt that misses the hole will also tell you a lot about the green. You can learn from this to have a better chance of sinking the return shot. You will also find out more about your style and any tendencies or bad habits that you are developing. If your putt stops short of the hole, on the other hand, you learn almost nothing.
With all golf shots, practice is vital, and never more so than with putting. This does not mean you have to hit the ball exactly the same way over and over. Your practice sessions can bring flexibility and new ideas to your game, because you can vary your usual style in practice time and try out all the putting tips that you find.