Tap Harmonics

i was wondering if anyone could help me with tap harmonics i can pull them off sometimes but i dont know how i do it it pisses me off when i do it once and then i cant do it agian so some tips or suggestions would be greatly appreciated

I find it helps to have a light touch, and let your finger "bounce" off the fretboard. Also, I have noticed that tap harmonics don't work so well on the lighter, unwound strings (G,B,E).

I'm sure you already know this, but just in case, you need to tap 5, 7, or 12 frets down from the fretted note in order to produce an audible tap harmonic.

it's all in attack:
Tapping harmonics became a real project for me when I procured my fretless: Suddenly I had to be a lot more accurate. Think more about pulling your fingers back up than putting them down- the cleaner you hit those strings the better, also the less time you're touching them, the less you mute them.