We heard it all so many times in our lives. Practice, Practice, Practice or Practice makes perfect. But sometimes you have to remember it's not just about the act of practicing but you ned to learn to practice properly.
This is something I've always been poor at. I'll pick up a guitar to 'practice' but will just end up noodling for an hour or so. I'll do the same sim-racing, I'll just load up a track and blast out a few laps and consider it as a practice. Neither of these are really practice.
I've been trying to improve how I practice, I've done this by adding a few things to my practice routines.
Never sit down and practice mindlessly. You should have a goal before you sit down to practice. It could be something simple like learning a small riff in a song you like or in racing it can be something like improving your lap times or consistency.
From these goals you can define a plan on how to practice. Find the tabs you need to learn, the scales you need to practice. Load up the right car/track combo to get rolling.
Now comes the most important part, you need to be able to analyse your practice session vs your goal. For my racing hobby this is very easy. There are a ton of online tools to analyse every turn and lap you do in a session. You can even compare your laps against some of the fastest in the world. This gives you a great way to set your goals for the next practice.
For my guitar playing, I've started recording all my practice sessions. I can go back and listen to everything to see what is and is not working. From there you can figure out your next goals.
So far it's been paying off.