Touch the tip or front edge of your tongue to the roof of your mouth just behind your teeth. Keep your jaw relaxed. Stop the air, then release with a puff.

Americans pronounce teamwork as TEEM-wurk (/ˈtimˌwɜrk/). Stress falls on the first syllable — keep everything else short and quick. You'll hear it in sentences like "Effective communication is the key to successful teamwork" or "The coach emphasizes the importance of teamwork and communication" — more examples below.
Record yourself saying "teamwork" and play it back. The mic stays on your device — nothing's uploaded.
2 syllables, 6 sounds. Tap a syllable to jump to its row, then explore each sound's mouth shape and how it's made.
Touch the tip or front edge of your tongue to the roof of your mouth just behind your teeth. Keep your jaw relaxed. Stop the air, then release with a puff.

Pull the corners of your lips back slightly. Arch the middle-front of your tongue high toward the roof of the mouth.

Press your lips together. Air flows through your nose. Vocal cords vibrate.

Round your lips into a tight circle. Lift the back of your tongue toward the soft palate and add voice.

Flare your lips and push them away from the face. Lift the middle of your tongue toward the roof of the mouth.

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

Click any sentence to see the full breakdown — every link, every reduction, every flap-T.
The textbook way isn't wrong — it's just not how anyone actually says it.
In "teamwork", the "k" is not released — the articulators get into position but hold without the burst of air. Air stops but there's no release burst — the articulators hold position.
Stress falls on the first syllable, not the others. Stretch TEEM — keep everything else short and quick.
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.