the biggest problem of not being able to play fast is excess muscle tension that builds up in your body while you play. Next time you start to play focus and try to connect with your body. Be aware of what's going on in both of your hands, arms, shoulders, neck, muscles between your shoulder blades, your lower back. it really good to have a mirror so you can see how you're sitting. are your borth shoulders aligned, is one shoulder higher than other? this is really crucial if you want to improve. How tens is your belly? Are you able to breath normally while you play? Write down on a paper all this parts of your body and rotate your attention. Then start to play a lick, scale, riff, that you struggle with, but do it like this:
1. set metronome to 60 bpm and play WHOLE notes (1 note per 4 clicks). don't bother your self if one note is longer than the other in the real lick, just play whole notes for now. the key here is that you learn to relax after playing each note. you have to be completely relaxed after you play the note. after you play each note rotate your awareness to all the parts of your body on your list and how you breathe.
2. set metronome to 80 bmp and so the same whole note thing.
3. set m to 100 bmp, do the same
4. set m back to 60 do the half notes (one not per 2 clicks)
5. set m to 80 and 100 with half notes
6. set m back to 60 do the quarter notes... then 80 and 100
7. then 60 80 100 with 8th notes
8. when it comes to 16th notes its better to raise your metronome for let say 5 clicks at the time. then find your max speed with 16th notes.
as soon as you realize that you have any tension in your body stop, relax, if you need to take a break for a minute, stretch what ever. and come back.
practicing is really a mental activity. you have to be focused and present all the time. i've read interviews with virtuoso violinist David Garrett. he practice in 20min time slots. after that he takes few minutes of. and then again. he's 100% focused on every detail. and this is really the only way to a high level of playing.
this way of practicing will reprogram your body and you'll get rid of any tension form your muscle memory. do this kind of practicing for 2 months and see what happens.
Playing with 'no tension' is really not what you suppose to do. controlling your tension is really the key to playing
one of the biggest changes i did in my playing is i became aware of what's going on in my body while i play. these are the main area
