Hi.
There are few important things that you should be aware when doing tapped harmonics.
First, the interval that you tap, octave works the best, then fifth, second octave etc.
Second, you have to tap right above the fret and not between frets like when you just fretting
with your left hand.
Third, lower strings are best for tapped harmonics since they have more "meat".
Forth, your sound should be well balanced, amount/type of drive and EQ setup,
sound with lot of low end/bass ain't gonna work well, try with more trebs instead.
So those are some "rules", everything else should come along with practice,
let me know if you need extra info.