Ask HN: Tips and tools to make a great screencast?

I love learning new programming languages or frameworks by watching screencasts. I've now designed a new language to build chatbots (docs here: https://hubtype.github.io/botSON - still working on it). Thinking about recording a screencast this weekend.

I'd like to know what you guys like about good screencasts. Should it be long and explain a full working example? Should it be a series of very short videos (egghead style)? I'm not a native english speaker, any tips on this? How about the style and tone of the speaking? What tools do you recommend?

Thanks!