Go for it! It's a lot of fun making videos, I do it for ferret care (like bettas, there are a lot of misconceptions out there)
It helps if you have a script or outline of what you want to say.
Here are some suggestions, they may be a bit redundant.
Tanks- whats appropriate, what isn't
Why feed a variety of foods
Cycling (and why it's hard to cycle small tanks)
Plants, silk vs natural. What are easy live plants
Heating your tank, why it's important
Supplies for your betta
How to do water changes (I've never really seen a vid on this)
How to vacuum gravel
I like to do how-to vids or info vids, and then some just showing off my animals. Good Luck!