First thing is first. Find your sweet spot on the harmonic. If you cant find one.. use more gain. Practice the harmonic first. syn uses his thumb.. I use my index. Figure out which works better for you. Once you get the harmonic down.. add step 2.. the bar. 3 5 7 and 12 are good starting points in the middle 4 strings. Best spots.
Same with pinches.. gotta find the sweet spots before anything. Sesrxh around.
Different things make for different sweet spots. Hope this helps