There are three skills that you need to acquire to become a better putter. You need to develop these skills by effective practice. The three skills are
1.Green Reading
2. Start the ball on the correct line
3. Roll the ball the correct speed
There are many ways to become better at reading greens. Basically, you want to develop your ability to observe and process the information. This means using your eyes, feet, and overall balance to gather the information. Some basic questions that you will answer are: What slopes do you see? Where does water drain off the green? What type of slope do you feel? What angle is the straight putt line? Is the putt uphill or downhill? Are there mounds and slopes in between the ball and the hole? What is the overall slope of the surrounding land? Do you feel the slope constant or changing as you walk around the green? These are just basic questions that you process
Your brain processes the information and then gives a calculation of where you should start the ball at the predicted speed. You have to develop these skills through practice. This is why I love practicing with one ball and putting each putt from a different location. This forces you to have to read each putt and therefore helps to develop your green reading skills.
This leads to to the second skill. Once you determine the appropriate starting line, you have to develop the skill to start the ball on the intended line. This skill is developed by working on proper technique. Essentially,the only technique you need to master is the ability to match path and face. What does this mean? Every shot in golf is really a relationship between your club path and clubface at impact. In putting, by far the most important ingredient to master is the clubface position at impact. If the clubface is pointing at the intended line at impact, the ball will start on that line. Optimally, the club path and clubface will match during the entire stroke which may help you produce 
a correct clubface alignment at impact. This skill can be enhanced by practicing better technique. Make sure you have some way to have feedback so you know that you are working on the correct mechanics.
One very simple drill to practice this skill is to put two tees about two feet in front of the ball on the intended line and put the tees about 3 inches apart. The tees form a gate. Your objective is to putt the ball through the gate. If you can do this, then you know you can start the ball on the intended line.
The final skill needed is to hit your putts the correct pace. Every putt has to match the line and speed. Your ability to hit putts with the correct speed is very crucial in making putts. I I believe that you should envision the ball entering the hole at the same speed every time. It has never made sense to me for a player to say “I think this putt is firm at this point”. I think it’s better not to think about the ball entering at different speeds. I think this leads to confusion.
My favorite drill to work on speed is to hit random distance putts. After you hit the putt but before you look up to watch the putt, you predict the outcome of the putt. For example, you hit a putt and you predict whether the putt will end up short, long, or just right. After doing this for a while, you will definitely become better at hitting putts with the desired speed. Then you can get even more specific by predicting 1 foot short and 6 inches right or 2 feet long and 1 foot left, etc. The more you practice this way, the more your brain becomes activated. This allows you to trust you skills.
One thing is certain. You will be a great putter if you read greens correctly, start the ball on your line, and hit the ball the right speed. You job is to determine which one of these skills is your biggest weakness. Once you know that, the next step is to create a plan to improve that area. The more your develop confidence and trust in your ability, the more good putts you are going to hit. Develop these skills and watch your scores drop.
