Practicespot – Remarkable resource for teachers (also by Philip Johnson), with many “free tools for practicing, teaching, and playing”, products, practice tips, articles, references/links, and more.
How to Practice – All practice, all the time. Tons of tips, articles,
Practicing a Difficult Passage Effectively – blog article by Jonathan West
Practice – Google books brings you a section of The Science & Psychology of Music Performance by Richard Parncutt and Gary McPherson
Strategies for Individual Practice – Google Books again; article by Harald Jørgensen
O.J.’s Trumpet Page will link you to a lot of good advice on systematic practicing by players such as Phil Farkas, Allen Vizzutti, Derek Reaban, Chase Sanborn, and Eddie Lewis, Wynton Marsalis, and others. I know, I know, except for Farkas, they’re all trumpet players, but even a blind hen gets a worm once in a while.
Power Practicing – a chapter from Eli Epstein’s book, Horn Playing from the Inside Out
Practicing for Beginners – from the Jackson, Longfellow, and Sheridan Elementary School Bands Website [Wisconsin]
Musician’s Practice Planner – by David Motto. Scheduler/Planner
Personal Practice Planning – article by Tom Heimberg. A compendium of books, articles, and ideas on how to practice.
The Musician’s Practice Log by Burton Kaplan. 80 p.
A Guide to Great Home Music Practice by Catherine Schmidt-Jones
Online Tuner – Slick online tuner by Seventh String Software. Also downloadable as a zip file.
Online Metronome – Slick online metronome by Seventh String Software. Also downloadable as a zip file.
How to Play the French Horn – Expert Village offers tutorial videos (131,362 at last count) on all kinds of subjects (like YouTube, except you learn something). This series of short videos (23!) is by Katherine Liesener. Topics include Adjusting Pitch with the Hand and with the Embouchure, Emptying the Spit [sic] Valve, Practice Tips, Training Methods, Stopping & Muting, Tuning, Greasing slides, Holding the Horn, Oiling Valves, Alternate Fingerings, Accents, Getting Started, Glissandos, Staccato, Playing Standing Up, Embouchure, Mouthpiece Pressure, Legato Tonguing, Slurring, Dynamics.