A guide to a good scream by a slightly educated fool(This guide is made, assuming that you have the basics for singing down)
-> Making sure you're doing it on a comfortable note where you can project comfortably
-> Do not try to be loud but this DOES NOT MEAN that you should be quiet or anything. Be comfortable with the sound you have and explore the limits of it by healthy projection. You'll have a much nicer sounding scream than what you'd have gotten if you had "pushed" to the loudness.
-> Your body not being stressed(do some body stretches and neck exercises before practice sessions. It helps a LOT)
-> BE HYDRATED! DRINK WATERRRRRR! I AIN'T GONNA BE SEEING YOU DRINKING COFFEE-
-> Making sure you're keeping that relaxed state
-> Using the right terms to describe your vocals and how you're doing it
|__ Pushing -> This term is dangerous, and even I use it sparingly in a good context. Instead, use "Exploring my limits and experimenting with what I can't and do"
|__ Belting -> Literally a projected voice with the most minimal amount, around your upper range. Anything more will be yelling.
|__ Healthy technique -> A technique that's sustainable and works for your body. Everyone is different but this doesn't mean you can casually project an epiglottis based vocal. Healthy technique IS sustainable BUT every technique has its own vocal limit.
|__ I'm straining -> If you're inexperienced, do "This is straining but I don't know what's going on yet but I should stop now and research about why this is happening."
If you know what's happening and this happens while you're doing a healthy technique, retrace your steps and if it doesn't make sense, and GO TO AN ENT, DAMN IT! CALL THE MARINES AND THE NAVY!
-> Lastly, knowing your limits -> You're not superhuman. Stop and rest when it doesn't feel right anymore or avoid doing vocals if you're not feeling well before practice.
Remember, DRINK YOUR WATER, YOU FU-