Practicing difficult passages

Keep in mind, you want to play at 70% of what you have.  If you play at 100%, it will sound desperate and no one will enjoy it.  You practice to the point that is 100% and you only use 70% of that to perform so you have the full control.

1. Set the metronome slow where I am confident to nail
2. Play the section without any mistake 10 times in a row
   Reset the counter when you fail and start over (this is the game part)
3. Set the metronome 2 clicks faster
4. Repeat from step 2)
5. When it got to the point it is too fast to repeat 10 times in a row, write down the metronome number and try again next day

Again, practicing should be fun, not torturing, or you won’t improve as much as you wish.
I highly recommend recording your practice when you are ready. It is important to check yourself subjectively often.