Here's something that helped me, FWIW. For about 6 years I played in a weekday-evening league on an nine-hole Par-3 course. We played every Tuesday night for about 12 weeks or so. I got pretty good at Par 3's, and now they don't bother me as much. So, if you've got a Par-3 course near you, maybe it would help to play it somewhat frequently, if possible. Doesn't take much time or cost as much. Maybe that would help?

On the question of keeping score against fives, this is something I've been doing for a long time. Now, wazmankg and valeogut are perfectly right (can you be "imperfectly right"?) about focusing only on the next shot, but unfortunately I lack the ability to heed such wisdom, so I keep score against fives. This way, I always know what kind of pace I'm on, relative to my goal of breaking 90 (which I achieve about half the time).

Yes, it adds pressure, and it's discouraging when you know that your chance of breaking 90 has dropped to zero (because that 8 you just took put you 6 over fives with only 3 holes to go). However, I also find that it helps me bear down and focus. Sometimes after a bad hole, I look at the card and can say, "OK, I'm still only 3 over fives, and there's a Par 3 coming up, so I can get a couple shots back here."

Possibly a matter of personal style. I do know a guy who doesn't keep score at all. He seems to really enjoy the game!