Press your lips together to stop the air, then release. No vocal cord vibration.

Americans pronounce ploy as PLOY (/plɔɪ/). You'll hear it in sentences like "Roy employed a ploy to destroy the toy".
Record yourself saying "ploy" and play it back. The mic stays on your device — nothing's uploaded.
1 syllable, 3 sounds. Explore each sound's mouth shape and how it's made.
Press your lips together to stop the air, then release. No vocal cord vibration.

Place the tip of your tongue against the alveolar ridge just behind your top front teeth, the same contact point as /t/, /d/, and /n/. The difference is what happens to the air: for /l/, you let it flow continuously around the <em>sides</em> of the tongue (that's why /l/ is called a lateral). Turn your voice on the whole time. Lips stay relaxed, no rounding or flaring. For the Dark L variant at the end of a syllable, also pull the back of the tongue up and back toward the soft palate.

Start with rounded lips and tongue shifted back. Glide to relaxed lips with the tongue arching forward and up.