Arizona State University
Arizona State University: Thoughts on Practicing
Many great tips and strategies are provided here to help with practicing. Although written for oboe players, the advice here can apply to any instrumentalist.
OpenStax
Open Stax: Catherine Schmidt Jones: A Guide to Great Home Music Practice
Offering good tips on practicing, this site goes into some detail on how to best use your practice time.
OpenStax
Open Stax: Catherine Schmidt Jones: An Example Intermediate Horn Home Practice
If you are a French horn player, you may get a good idea of how to practice from this resource. It provides general ideas of what your practice routine should include.