Here's two bullet points from Mr. Hess:
- Do NOT compare yourself to your friend. Do not let your friend (or anyone else) set the standard for you to aspire to. One should have fixed in his/her mind the vision of the type of player one wants to become. Generally speaking, you don’t want your “next door neighbor” to be the definition of your ideal long term “vision”. If I could magically take your friend’s skills away would you feel better about yourself simply because he was not as good as you? Keep in mind that your skills would be the same as they are now, the only difference is that your friend’s skills were taken away or diminished. Your attitude about your own progress should be centered completely around where you are in the journey to realize your goals.
- After you have reconciled your thoughts with the first piece of advice, you are ready for the second. In general, the greatest players are not great because they were naturally talented. In every case, truly great players become great (and make a lot of progress in relatively shorter periods of time) because their practice habits are EFFECTIVE. You see, they not only put in the time and effort as you do, but that time and effort is focused and effective. It appears that your practice habits have not been effective. I do not believe you lack the necessary potential to make significant progress. You just aren’t being effective. You seem to believe that you “CANNOT”. I propose that you can, but that you simply “HAVE NOT”. Certainly you are trying, but the efforts are bearing little fruit…
That is two pieces of great general advice: You suck or not on your own merits, not the relative merits of others, and greatness comes from effective practice. As I started out, "practice makes permanent, perfect practice makes perfect".
He further goes to how of the practice, getting to a very specific piece of advice on the subject at hand. He had a student who had problems playing the intro to "Stairway to Heaven". Now, I personally cannot and do not want to learn the intro to "Stairway", but that's the facts of this case. The student played the intro from the beginning, but had the problem at the fourth chord, a D/F#. The solution for him was to stop hitting the parts he knew (the first three chords, in this example), and focus on the specific part that was the trouble.
Hitting the previous chapter, the video uses the example of Tiger Woods working on sand traps. He went to the sand trap and practiced that. He didn't start at the tee. If you have a problem point, don't use your practice time dawdling on the stuff you can do well, but jump directly to the part where you suck.
Look here for further reading.