Raise the back of your tongue to touch the soft palate (velum). Stop the air, then release.

Americans pronounce choreography as kor-ee-AH-gruh-fee (/ˌkɔriˈɑgrəfi/). Stress falls on the third syllable — keep everything else short and quick. You'll hear it in sentences like "The choreography in the dance numbers was spectacular".
Record yourself saying "choreography" and play it back. The mic stays on your device — nothing's uploaded.
5 syllables, 9 sounds. Tap a syllable to jump to its row, then explore each sound's mouth shape and how it's made.
Raise the back of your tongue to touch the soft palate. Add vocal cord vibration, then release.

Curl or bunch your tongue without letting the tip touch the roof of your mouth. Brace the sides of your tongue against your upper back teeth, and round your lips slightly.
Relax your lips, jaw, and tongue completely. Drop your jaw slightly and keep the tongue neutral.
The textbook way isn't wrong — it's just not how anyone actually says it.
Stress falls on the third syllable, not the others. Stretch AH — keep everything else short and quick.
Don't pronounce the third syllable too fully. The unstressed syllable reduces to a schwa — the lazy "uh" sound — in casual speech.
Americans use a relaxed retroflex R — the tongue curls back rather than rolling. The R is one continuous sound with the vowel before it, not two separate sounds.