To help develop a solid technique, I would recommend incorporating this routine into your practice. I have found this routine to be very helpful. It makes me feel fundamentally solid when I do it regularly. Full disclosure... I can't take credit for this. I'm pretty sure that these particular etude pairings came from my lessons with Carl Lenthe when I was a student at Indiana University.
1. Choose any Bordogni etude and go methodically through it one phrase at time. First, sing the phrase, then buzz the phrase, then play the phrase.
Kopprasch (play all repeats on all exercises)
1. #1 or #2 tenuto and marcato
2. #3 or #11
3. #4 (play double tongued when repeating)
4. #5, 7, 8 or 9
5. #6, 10 or 15
6. #12, 13 or 14