I consider myself an above average putter. Its probably the only thing I'm really good at in golf, consistently. I spray the driver, I chunk chips sometimes, if I was a better iron players I'd be a scratch golfer, but I've always been good at putting.
my thought process is pretty straightforward. You need to be an expert at jamming a ball into the hole from 3-5 feet. I mean like it shouldn't be hard for you to make 10 in a row on the practice green, and you're furious if you miss even one.
once you have this small, extremely important skill dialed in, THEN you can be a great putter from any distance because now the only thing you have to concern yourself with on any putt, is speed control. You learn this by practicing lagging from 25-50 feet, with the goal being to leave the ball within a 3 ft circle around the hole, which since you're an expert at 3 footers, doesn't bother you in the least. I like to imagine a 50 gallon drum sitting over the hole, I want to hit the 50 gallon drum but if I miss, try to keep it within that visual circle around the hole.
finally, speed is more important than line. you can miss the line by 2 inches and the ball will still go in the hole at the right speed.
once you get really good at putting, you just think you can make every single putt on the green. You feel like the free safety that gave up three 60 yd bomb TD's to Randy Moss in the first half, and in the 2nd half you're still trash talking about locking him down.