Sometimes, taking the game to the course is a battle. When describing implementing a swing change, Tiger said, "first I understand it, then it looks better, then it feels better, then it performs on the range, then it performs on the course, then it performs in a tournament." Some times he would comment, "I just need to put in more reps" when he liked what he was working on, but it wasn't showing up on the course as well as practice.
It sounds like you are doing well on the range/in warm-up, so then it becomes more about what changes on the course from the range. A simple guide is to make practice more like on course, and make the on-course feel more like practice. I find when it breaks down on course, then there are a few common culprits.
1 - alignment. A lot of golfers have really bad alignment on the course, but find their way to an okay alignment on the range when they get multiple reps.
2 - pre-shot routine. They have a varied preshot routine and never practice it enough to make it help them. They do something during every shot and that makes it hard to build a pattern.
3 - time in between balls. The more you want things to transfer, the more you want gaps in between balls and avoid hitting the same shot to the same target over and over.
4 - practice walking into the shot. This is similar to the routine thing. Here's a short video of one style of practice I use where I have my student practice walking into shots instead of just hitting. It's a sped-up version of practicing alignment, get set, execute.
Also, practicing on the course has a huge benefit to on-course performance. It could be handling uneven lies and such that makes everything feel different.
I hope that gives you some ideas,
Happy Golfing,
Tyler
