The Play Smart blog at Golf.com recently did a piece on “Heads Up” putting with some good tips:
https://golf.com/instruction/putting/heads-up-putting-technique/
I think a key one is to not necessarily look at the hole.
“On breaking putts, don’t look at the hole. Look at the point where the putt will break off. On putts without a severe break, I’ve found success looking at the entry portions of the hole: The left edge, for instance, or the back of the cup. Remember that looking up isn’t the same as looking at the hole, so pick a specific spot.”