YouTube SEO is simpler than people make it out to be. There are three things that actually move the needle, and a hundred things that do not. Let us focus on the three.
1. The title
Your title does two jobs. First, it has to match what people are searching for. Second, it has to make someone click. Those two jobs pull in opposite directions.
Start with the search term. Use YouTube autocomplete — type the start of your topic into the search bar and see what YouTube suggests. Those suggestions are actual search queries with real volume. Pick one that matches your content and put it near the front of your title.
Then add a hook. "How to Edit Videos in CapCut" is searchable but boring. "How to Edit Videos in CapCut (the 5-minute method)" gets clicked. The parenthetical is doing the work.
2. The thumbnail
Thumbnails matter more than anything else. A mediocre video with a great thumbnail will outperform a great video with a mediocre thumbnail. YouTube knows this, so it ranks click-through rate heavily.
Rules for thumbnails: one clear subject, big readable text (3-5 words max), high contrast, a human face if you can. Avoid clutter. Avoid tiny text. Avoid making it look like every other thumbnail in the niche.
Every big YouTuber A/B tests their thumbnails. You should at least make two and pick the better one.
3. Watch time and retention
YouTube does not really care about subscribers or likes or comments. What it cares about is watch time. If people watch your video all the way through, the algorithm shows it to more people. If they drop off at 30 seconds, it buries you.
That means the first 30 seconds of your video has to hook viewers and deliver on the promise of the title. Stop with the intro animations. Stop with "hey guys, welcome back". Get to the point.
What does not matter much
Tags — barely matter anymore. YouTube figures out what your video is about from the title, thumbnail, and transcript. Do not waste 20 minutes filling in tags.
Description length — longer is not better. A clear two-sentence description with a link is fine.
Uploading at "the perfect time" — meaningless. Your video will be recommended to people over weeks, not hours. Upload when you finish it.
For a broader look at choosing where to publish, see The 5 Best Platforms to Upload Your Marketing Videos.