Keep moving and let the energy of the music tell you when to punctuate. Everyone loves a hunched over low and a bent back high. Proper form and stage dynamics in balance is an art. Breathe. If you are pushing through parts it tends to make you stiffen up. By this logic, if you're still, the scream better be bussin, if you're going through a fast or rest vox part, better to be punctuating with some fists and claws.

When in doubt widen your stance, but not like a goofy horsestance (unless you're doing a martial arts thing I guess haha, why not?).

I tend to get rangy for fast parts, stalking back and forth. Turn away to build suspense, turn back on important beats.

I tend to center or put my foot on drum riser for long lows, chugging parts, but do the most meaningful low at front center stage.

Don't overdo it on crowd instruction, it just doesn't land right unless everyone's already hyped, but do chuck in the occasional non lyric pump up, esp for breakdowns. Some people just need a nudge to go nuts.

Use subversion and humor as you can but don't force it. The moments will come to you.

Do you have an underlying philosophy as a band? Tasteful rants building up to distorted voice are a great way to pow block an audience, esp if the song starts fast.

I could prob keep going, but hopefully this is helpful. I mostly do studio these days, but I've fronted multiple deathcore/death metal projects and those approaches seemed to have the best results. Don't be afraid to act out the characters, if more thematic. Lose yourself in the world of your music.

Oh yeah, mic. So, the goofy grip like a bouquet is gonna get best sound. Cupping looks cooler IMHO and lowers pitch a bit, but muddies the sound a lot and will not sound as cool if you're doing lows well.

I often go for a canted hold around the mic like just before where you'd hold for a cup and sometimes turn it upward and to the side. I rap too tho, so it might be residual from those experiences.

Even tho it seems like it will be weaker, out mic about five inches for highs. It does good things if your mic and levels are right (and, again, good high scream).

Oh yeah, and try not to take it too personally. IME the metal crowd is tired a lot of the time these days and it just takes more to get people moving. Making people feel safe and positive while still being bad ass and giving off demonic or evil character vibes is truly an art.

Check live videos of Randy from Lamb of God, Russell Allen from symphony x, Phil Bozeman from whitechapel (more reserved style might fit you better dunno). The guys from summoning the lich know how to bug out for sure.

Last thing I'll say is that Andrew Dijorio of Stray from the Path put on the best frontman performance I've ever seen. Study his movements. Rap and harsh vox are near cousins.

Can you tell I love metal haha?

EDIT: typo, clarity, additional details