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

Americans pronounce cruel as KROO-uhl (/ˈkruəl/). The L in "cruel" is a dark L — the back of the tongue rises toward the soft palate, adding a small "uh" quality before the L. This is called the Dark L vs Light L, and it's one of the defining features of casual American English. It comes out as KROO·uhl. Stress falls on the first syllable — keep everything else short and quick. You'll hear it in sentences like "Two students proved the rule was cruel".
Record yourself saying "cruel" and play it back. The mic stays on your device — nothing's uploaded.
2 syllables, 5 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 (velum). Stop the air, 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.
Round your lips into a tight circle. Let your tongue rest in the middle of your mouth, slightly raised.
The textbook way isn't wrong — it's just not how anyone actually says it.
The L in "cruel" is a dark L — the back of the tongue rises toward the soft palate, adding a small "uh" quality before the L. Dark L adds a small schwa-like "uh" before the L. The back of the tongue lifts toward the soft palate.
Stress falls on the first syllable, not the others. Stretch KROO — keep everything else short and quick.
Don't pronounce the first syllable too fully. The unstressed syllable reduces to a schwa — the lazy "uh" sound — in casual speech.