Try to establish some kind of technical routine for yourself... Which should include, but not limited to: Scales and patterns, long tones, tuning exercises, overtones, articulation exercises, etc.
Some books that will help you with that:
Les Gammes- Londeix
Daily Studies- Teal
Daily Studies- Kynaston
Top Tones- Rascher
Next comes etudes. Etudes do work on certain physical technique, but also musicality. They should challenge how your interprut music, as well as build your technique. Etudes should be challenging, but don't spend more than a week or two on an etude. 2 etudes a week (slow/fast) I think is a good routine. Here are some suggestion for someone of your age/level.
48 Famous Studies- Ferling
Slected Studies- Voxman
24 Petite Etudes Melodiques- Senon
32 Etudes Melodiques- Senon
Etude Expressives- Amellar
Good luck with your playing, and establishing a good routine. Here's something I think works (and I know some people will disagree), but when you practice it should be divided into three parts: Scales and Technique, Etudes, and Repertoire. Each one of these areas should be practiced for the same length of time. Don't practice Ibert more than you practice your scales, don't practice your scales more than your etudes. That's not my method...it's Londeix's, and it works.