2. Listen to music.
It has always surprised me how many horn students don’t listen to music much. Periodically someone will come in to play for me and be working on Mozart that has never heard Mozart!
Buy a recording or three! I have a list of suggested, essential recordings in my Horn Articles site, and of course I am partial to my two solo CDs also. It is a part of building your mental picture of pieces, knowing what it is supposed to sound like helps with accuracy, tons of things.
Effective practice of anything certainly includes listening to music. Listen to music! There is a way that especially the standards need to sound that you really can only achieve if you have a strong mental picture of how they need to sound and that picture is only built up by listening to music.
For excerpts HornExcerpts.org is a start and a great one but also listen to full pieces of music! It is the only way to get that mental picture clear.
So to become a horn expert be curious and listen to a lot of music. Part 3 tomorrow.