The YouTube Metadata Helper tool is a tool I made for myself after spending some time researching how to optimize the textual content of a YouTube video. Of course the purpose is to improve the video's ranking on YouTube. I may be countering myself by putting it out in the public, but I don't have a desire to maintain an identity guard on it.
If you use it, I hope it helps. It's based on the book YouTube Channels for Dummies (1st Edition), which is now a little outdated since it came out in 2015. There's a 2nd Edition apparently coming out in September, so I might be updating the tool after I read through it.
For desktop or laptop should be 100 characters, 75 for suggested videos.
For mobile should be 40 characters, 30 suggested suggested.
Keep series identifiers, such as season and episode, at the end, preferably outside of the important characters range.
500 characters limit.
30 character per tag limit.
One or more words per tag.
Maximum of 5,000 characters.
Explain in great detail what the video is about.
Use a shortlink to a web page about the video, not a home page.
The first paragraph will show up on desktop search, nothing on mobile.
Use shortlinks to the channel about page, other related videos or playlists, social media, or a web site, but add them near the bottom of the description.