Short version:
be very precise with the math.
don't die it in the hole.
don't aim at the front of the hole on breaking putts but aim at the side as you visualize the curve
err on the high side.
better to slightly miss the ding into the break than to miss it with the break.
putts aren't equal. a 10 foot putt dead up the hill is better than a 10 foot pin high putt on a sidehill lie. landing spots matter.