Raise the back of your tongue to touch the soft palate. Add vocal cord vibration, then release.

Americans pronounce gaining as GAY-nuhng (/ˈɡeɪnəŋ/). Stress falls on the first syllable — keep everything else short and quick. You'll hear it in sentences like "Electric vehicles are gaining popularity as an alternative to gasoline".
Record yourself saying "gaining" 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.
Touch the tip or front edge of your tongue to the roof of your mouth behind your teeth. Air flows through your nose.

Relax your lips, jaw, and tongue completely. Drop your jaw slightly and keep the tongue neutral.
Lift the back of your tongue to the soft palate. Lower your soft palate to let air flow through your nose.

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.
Stress falls on the first syllable, not the others. Stretch GAY — 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.