You can have the perfect stroke, put a perfect roll on the ball, but if you can’t read greens, you will never be a great putter.
Reading greens has always been a strength of mine, and although there is an art to it, I’m going to share the process that I use and teach.
The first thing you need to determine is if your putt is flat, uphill, or downhill. If there is a little bit of both in the putt, then analyze whether it’s more one way or the other. The best place to view this is NOT behind the ball but to the SIDE of your putt (lowside specifically). Try to quantify the uphill or downhill as well. For example, “This putt seems to be going about ten inches uphill.”
Once you’ve completed this, then it’s time to figure out the break of the putt. Start from behind your golf ball looking at the hole. You’ll always want to determine break starting from the center of the hole going OUT. Ask yourself, “If I roll this ball straight at the hole, what will happen? Will it go in? Will it miss left or right? By how much?” If it appears that the ball will miss 12 inches to the right of the hole, bring your aiming point 12 inches to the other side of the hole. Once you’ve found your new target, focus on it and ONLY IT and try to roll your ball to it.