1.Make A Decision
Have an idea about what you want to get out of learning a musical instrument. Do you want to play in bands, become a session player, record in the studio or just play for fun? This will open your mind to what you will need to learn to get there.
2.Deliberate Focus
Choose something you find difficult. It should be a struggle. If not, you are in your comfort zone and not getting betterThe simple way to getting better at any musical instrument is to work on what you struggle with. Nothing is difficult, just unfamiliar. By working on what is outside your comfort zone you can start to add more and more to your musical toolbox. Most people like to pick up their instrument and just play. There is nothing wrong with that but make sure you know the difference between playing and practice. Practice is working on your weaknesses.
3.Be Honest
Learn to hold yourself to a high standard where you can recognise shortcomings in your playing. In order to find your weaknesses you need to be honest with yourself. You may not be practising enough, or you're always playing what you already know how to play, or are ignoring techniques that you know you should learn. You need to have the clarity to realise that this isn't how to get you to the next level. Doing so will change the course of your future.
4.Cultivate identity & Belief
A huge part of developing good habits is to work on your sense of identity. Rather than constantly having lots of goals that you temporarily stick to, become the person who is determined and excited to work on their musical skills. Make that identity a part of you. If you believe that practice is a chore it will become one. If you see it as an essential part of becoming a great player then you will relish your practice sessions.
5. Build A Sanctuary
Take your instrument out of its case, don't leave it in another room. Organise and set up a beautiful area that draws you in and inspires you to play. Here's mine:

6.Repeat Correct Movements
Mr Miyagi knew what he was on about with "Wax on, wax off".
If you ignore mistakes in your playing you will be reinforcing those errors which will then become much more difficult to iron out. If you want to play fast, first learn the passage very slowly but with perfect form. Then build up speed from this point. Those correct movements will become ingrained into your muscle memory and this leads to effortless playing.
7.Schedule
You are much more likely to practice if you make a written commitment to do so. Building great practice habits could be the most important thing to learn in your musical journey. Muscle memory and good behaviours are built over time and the more consistent you are the easier music becomes. The more you learn, the clearer the connections become between all the myriad musical elements. 10 minutes a day is better than one hour once a week.
8.Be Persistent
Develop grit and determination: you will hit roadblocks but Over time you will improve. If developing good habits and being disciplined and focused were easy we'd all be millionaires with great bodies. Struggle, lack of motivation and direction, frustration, impatience, boredom and - especially - distractions are all going to rear their ugly heads and try and barge you off the path to your success. Developing grit and determination is like being able to defend yourself against someone wanting to physically harm you. It's very important to develop this mental self-defence.
9. Measurement & Feedback
Track your progress and get honest feedback; from a teacher, bandmates, friends or by recording yourself. Management guru Peter Drucker once said, "What gets measured gets managed". Write down what you will practice, when and for how long. This will help build the habit. Using a practice journal is a great way to start logging your sessions and gaining more direction by setting goals and sticking to them.
10.Play & Listen
Use your new skills and immerse yourself in the beauty of the art. You're reading this because you want to improve your musical skills as you love music. The fuel to keep going on is found in the wonder and joy found in music. Involving yourself as much as you can will light a fire that will never go out.
11. Enjoy The Journey
There are very few things in life more pleasurable than music and dedicating yourself to mastering a craft. We all live in a world of limited attention spans and TV shows that promote personality over talent. Music teaches you art, science, teamwork, empathy, discipline, focus and meta learning. It is worth putting in the effort and you will enjoy the added benefits you'll get in other areas of your life.
I hope you use some of the ideas in this post and I'd love it if you shared it to spread the word about this important aspect of music!