Screaming
I didnt want to touch on this subject because its a dangerous thing to try. Its also really difficult to explain it. I would like to issue a disclaimer that I dont recommend using this technique for more than a few minutes at a time. Id say more than 10 minutes per hour is excessive until you have mastered, mastered, mastered this technique.
The best way to scream is to create the distortion with moisture from the back of your throat. The sound will come from a strong, really strong diaphragmatic push (if you cant breathe from your diaphragm, or dont know what Im talking about, refer to my first article here. This push will feel like when you pressurize your breath, but you wont be capping it off with the muscles of your throat. If you dont understand, just give it a try. Pressurize your breath, now scream with that pressure.
Of course, pushing from your diaphragm isnt the only way to scream. You can also push from your chest, which is what most amateurs do. This not only lasts shorter, but it also has a greater chance of straining your vocal cords. I highly recommend practicing screaming from your diaphragm.
To find that perfect spot of distortion, start by screaming at lower tones and finding your distortion at the low tones. Keep that distortion and raise up a few steps. Repeat. This will preserve your voice more than just diving in and hurting yourself will.
