Titles
Say what the video is about in plain words people would search: "Why octopuses have three hearts" beats "You won't believe this!!"
Keep the most important words at the start. On phones, long titles get cut off.
Descriptions
One or two sentences that add something: the source of a fact, the name of a place, a question for the comments. Descriptions are read by search engines too.
Hashtags
Two or three relevant ones are plenty. #Shorts isn't needed for a video to count as a Short, but it doesn't hurt. Avoid long lists of unrelated tags - they look like spam.
Captions for other platforms
TikTok and Instagram show your caption more prominently than YouTube does. Write a first line that adds to the video rather than repeating the title.
TallClip writes a title, description and hashtags for each platform with every video, which you can edit before posting.
Title formulas that work
The question: "Why don't penguins' feet freeze?"
The surprising statement: "The Eiffel Tower grows in summer"
The how: "How sailors navigated before GPS"
The list: "Three inventions that were accidents"
Each is clear about the topic and gives a reason to watch. Avoid clickbait that the video doesn't deliver - viewers leave, and YouTube notices.
Thumbnails for Shorts
Shorts in the feed don't show a thumbnail - they just play. But on your channel page and in search, a frame from the video is shown. Pick a clear, striking frame as the cover where the platform lets you.
On TikTok and Instagram, the cover image matters more because your profile grid is made of them. Keep a consistent style so the grid looks like one channel.
Don't over-optimise
Stuffing titles with keywords makes them harder to read and looks like spam. Write for a person first. Search systems are good at understanding plain language.
Questions
Do Shorts show in YouTube search?
Yes. A clear title helps a Short turn up when people search for its topic, long after it's left the feed.