In my opinion, the best way to learn to putt is by first learning the compensated distances, and then you can get a better feel for left and right break. Here's how I putt, maybe it will help.
First, I judge length. I don't think about left or right break at all. lets say I have a 25 ft putt. If the putt is uphill 0 inches I always give it 2 more feet (27 ft). If it is downhill 0 inch, I give it about 1 more feet (26 ft). Moving on to larger deviations ...
On all putts that are uphill 1 or more inches, I add the uphill figure but in feet to my putt plus 1. (e.g. 25 ft putt, 7 in uphill, I will hit approx. 33 feet. 25 + 7 +1)
On all putts that are downhill 1 or more inches, I subtract about 60% of the downhill figure in feet. (3 in = subtract 2 feet, 4 in = sub 2.5 ft, 5 in = 3 ft, 6 in = 3.5 ft , 7 in = 4 ft, etc.) 25 foot putt, 10 in down hill I would putt about 19 feet.
Now the way I read the greens for break is in sections, 3-4 boxes at a time starting at the putter, and I adjust the putting line every section according to what that section should do. Really judging the break just takes a feel that you can only learn by playing. Hope this helps, Good Luck