I know that all my students have been listening to every word I say and doing everything I suggest and playing the most awesome golf ever!
Or, sadly being human, some things stick some don't, some things are easy, so we do them with regularity, and some things, (everything worth having in life) take effort.
So let's go on the assumption that proper practice procedures (there's that pesky word again) have been established. We all, (no matter whether amateur or tour professional) make mistakes while playing.
The key as I always say, it's about the next shot!
Do not let a bad first tee shot put you in a negative mindset for the next several holes. Shake it off, focus forward, you have 17 more tee shots to go. Better to tee off with a mid iron, get the ball in play in the center of the fairway, than to let ego let you whip out the driver, put it in the alligator pond, and lose your ball (the expensive one, yeah that one!)
Do not shoot for every flag. It is better to be on the green and having a fair chance to sink the putt, than going for the 'sucker pin' at the front of the green behind a coffin bunker and either being in the bunker with no green to work with, or overshooting the green and now have to chip back and try to get up and down in one.
Golf is a game of strategy, learning how to hit the ball is a must, learning how to play a golf course is more than how far can you drive the golf ball! If your scores are not dropping, but your actual ball striking, distance control and club selection in your estimation are improving, take a look at how you are getting around the golf course. How your partners are playing the golf course may not be the way you should be!