Putting is the great equalizer. Bomber or hacker we all have to find that hole. The two biggest problems with dropping putts are hitting putts on line and pressure.
First, answer the question of whether you can hit a putt online to a target. Setup a straight putt of a few feet with a small ball marker as your target. Grab your putter and while looking at your target aim it. When you are comfortable that the face should be aimed directly at the target look down and see if it looks like it is pointed at the target. It will most likely look open or closed to your line. This depends on the variance in your binocular vision.
Now hold the putter in place and move your stance until the face looks like it is online with the target. This may mean an open or closed stance with the ball forward or back or maybe you just need to be closer or farther away. There is no right answer for everybody. Just play with the different ways to set up the putt until you see the same thing looking at the ball as when you look at the target.
Once you get comfortable with your aim and stance you should be able to make at least one out of three on any putt of 10 feet or less. If you are still having trouble with this you are most likely too caught up in mechanics and are not letting your natural athletic ability help you hit your target. Focus on a target, be it intermediate or not, and just focus on hitting the ball at or through that point and nothing else. Once you can consistently make one out of 3 you are ready to add some pressure.
The big reason that most of us have trouble taking our game from the range or putting green to the course is that we do not practice with pressure. To add pressure you need to have a competitive outcome to the shot/putt. With putting I like to make up games that reward good habits under pressure.
My current favorite is to take 3 balls and count makes as birdies and missing all three as a bogey. For added pressure, all putts must be long enough to have gone in if they were online also, any putt that is not a grip or less from the hole must be made to collect a birdy otherwise a bogey is added to the card.
This game can be played alone or with someone else. If it is just you on the green, play at least 10 holes and to win you have to be at least 1 down. If at any time during a game you reach 10 over you have lost and must start over. when competing against someone the lowest score wins. Play this game with the pressure of not leaving the practice area until you have won a game and see how good your skills are.
Like every other shot in golf having confidence in how to make the ball move where you want it to and then reacting to the target under pressure is what lowers scores.