What's the most difficult part of making a coding screencast video?

Here are just a few things that are both difficult to execute and important. After 100 videos on YouTube these are what I found to be the most important.

1. Audio Quality and clarity.
2. Being on topic
3. Making it easy to follow and entertaining.
4. Making sure it's watchable on a phone, tablet and Desktop.

I have been recording dev screencasts off and on for the past 12 years. Mostly off though. I am also in the progress of getting back into it right now. I wish you the best of luck.
Here are my thoughts:

1. Audio is more than half the video. If your viewers cant hear you or the audio is crappy, people will leave. Very quickly. People can and do tolerate poor video. But not audio. You can buy very affordable "lav" mics on amazon or other marketplaces. I like the "PurplePanda" one. It was like $30. Great start

2. The better graphics your computer has, the better your recording will be. Since most screencasts do not use external cameras (unless you are wanting to do a floating head video with it).

3. My biggest struggle is talking pretty fast. When I get into a groove, then I tend to speed up a bit. Some people like it, some do not. I try to make an active effort to slow down my speech to a reasonable speed.

4. Make the code viewable on screen. I have seen lots of people full screen record their IDE and the publish it. This can be super hard for people to see in the video, and harder to follow along. Most videos are recorded at 1080p resolution (or 4k). Be sure to use a good screen cast recording software that you can specify the video recording area. I like to use "open broadcaster system" aka OBS. It is open source and cross platform. But can be tricky to setup. (PS: I do have an article on my blog of how I set it up on Windows if you are interested)

But seriously: Audio. Audio. Audio.

It slows my computer down too much.