Hello WhiteEagle!
We usually think in terms of describing out loud as speaking. What I do is speak into a recorder to record my voice. I just start speaking without editing my words, they just start to flow.
Since, I'm assuming that sign language is your language of choice, why not try video taping yourself. Start describing in detail in sign without editing your signs. Be as descriptive as possible. Paint a picture with your signs.
What's great about sign language is you can actually be MORE descriptive than spoken languages. Like Alex said, a picture is worth a 1000 words. One of your signs could be many spoken words.
And just go with the flow. If a picture is there for 1-2 seconds, let that be okay.
Happy streamming!
