The ability to play from memory is, like most everything else on trumpet, practice-related. Iow, the only way to really achieve this skill is by requiring yourself to do it!
Try these ideas:
1. While looking at the music, blink your eyes rapidly numerous times, as though taking a snapshot of the sheet. (This suggestion came from Sam Goldfarb, who was a Benge clinician for many years).
2. Sing the song, out loud, while fingering the notes on your valves. Working phrase by phrase, first sing/finger, then close your eyes and attempt to play the phrase without looking at it.
3. Learn to use solfege, either with solfege syllables or with numbers. Learning to recognize intervals, arpeggios and scale passages by type, and analyzing the form of the piece is also helpful. Sing the piece, using the syllables or numbers. (this also helps with transposition, btw).
4. Try to memorize the ending of a movement first. Usually when a memory lapse occurs, it's because the performer always started practicing from the beginning of the piece.
5. Develop your ears. There are several ear-training programs available in software. Check out NotationStation, Ibis software (Play It By Ear and Rhythm Ace, which is for rhythmic recognition), Auralis, etc. If you understand what you're hearing you'll be better able to reproduce what you hear inside your head.
6. Try to play along with recordings, or better yet attend a jam session or two<!>
Hth, let me know if you'd like any additional ideas, and how these worked for you.
Jeanne G Pocius
> Can one say a song is truly in their repertoire if they haven't memorized
> it? Out side of "scales" and some "warm-up drills", it seems that no matter
> how many times or how familiar I am with a song, I still rely on having
> the music before me. Is this normal or some sort of a crutch? I marvel at
> those individuals who seem to "memorize" a song with very little exposure
> to the written music.