OpenStax
Open Stax: Catherine Schmidt Jones: Scoring Music: Write for Specific Instruments
If you are interested in arranging your own music, you should check out the tips offered at this website. Including a history of how music was arranged, this site also gives several good ideas of how to make your arrangements interesting.
San Diego State University
Orchestration
Through playing "Orchestration," students learn about each instrument and the group to which it belongs. Actual instruments should be shown and demonstrated in class prior to playing the game. Create this fun card game for your music...
OpenStax
Open Stax: Catherine Schmidt Jones: Orchestral Instruments
This is a brief introduction to the various instruments on the modern orchestra. It is broken into sections based on the instrument families. Each instrument is briefly defined.