Not easy, especially off a hard shot bouncing high to you.
1. Stay solid, all body parts forward or stable.
2. Fully turn, more than normal, your upper body.
3. Hard forceful high to low stroke, with all your body weight behind it.
4. For me, best to use a conti grip with a SLIGHT eFOREhand flavor, taken very late, almost level with my hitting shoulder.
5. Targeted height is 1' over the net. The ball needs enough spin and ball speed to land into NML.
6. Full followthru across your body and low to add some sidespin to the underspin.
No 5 is the key, you have to slice hard and low over the net, but hard enough so the low net clearing ball goes all the way to at least NML.
For most good players who can hit this shot, it comes and goes depending on who you are playing, and of course how you're playing.