Fix the cause of common mistakes.

For this method you will need a selection of pieces and a notepad.

Play through your music and each time you make a mistake stop and mark the music. Once you have finished one piece go onto the next. Try to pick a few pieces in different styles.

For each place you marked a mistake try to decide what caused that mistake. Was it fingering? How about embouchure or breathing? Once you have identified the cause add it to your list.

When you have finished listing the causes of your mistakes re-order them so that the most frequent are at the top of your list and the least frequent are at the bottom.

You can now focus your practice on the areas at the top of your list.