I'm in the middle of designing an online course and I've discovered that the technique of live drawing while speaking used in Khan Academy is really quite hard

I'm in the middle of designing an online course and I've discovered that the technique of live drawing while speaking used in Khan Academy is really quite hard to do well. I certainly don't have the natural ability to do this (perhaps I need a lot more practice) and it's given me a good appreciation for the work that Khan must have put into it. My technique is to prepare slides with a script and then record myself presenting them. It's not nearly as nice, but at least I can do it.