Turn the gain down on your microphone, or hold it farther away from your mouth. Freestyle as loud as you can, like you are yelling in a crowded room. It’s not that easy and it’s a real workout for your diaphragm. Make sure you don’t go too loud or use a raspy tone. Be careful to protect your voice.
There’s a few different ways to shout-style. Some people naturally use an angry-shout mode, but you don’t need to sound mad when you are shouting; you can also be happy, excited or just authoritative. You will have to use different techniques with this style. It’s usually better to use simpler rhythms and shorter phrases that you can really belt out.
Some people are naturally very good at this. The physical workout will help your freestyling all over, and the practice could come in useful at times when the mic is broken or the room is loud. Another practice for your mic technique is using shout-style but not actually increasing your volume over the PA by remembering to move the mic away from your mouth when your volume is loud (see “Mic Dynamics”). Some people really express a different personality using shout-style!