Excerpt from the article by Brian Dean and published on Search Engine Watch:
"If you take the time to optimize your videos for SEO, you'll get significantly more traffic than your competitors.
It's not nearly as complex as Google's famous 200 ranking signals, but YouTube's algorithm is no joke. It takes dozens of signals into account for ranking videos in YouTube search.
1. Write Super-Long Video Descriptions
The more YouTube knows about your video, the more confidently it can rank it for your target keyword.
But more importantly, YouTube uses keywords in the description to rank you for super-long tail keywords.
Make sure your video descriptions are at least 200 words.
2. Optimize Around "Video Keywords"
Before deciding on a keyword for your video, check to see if there are video results on the first page. If so, that's a keyword you should strongly consider because you can potentially get your video ranked in Google and YouTube.
3. Get More Video Views From Online Communities
Share your video liberally on online communities. This will hook your video up with the type of quality, high-retention views that YouTube likes to see.
4. Encourage Subscribing and Liking
Subscribing and liking are two of the most important user experience signals that YouTube uses.
At the end of your video, give people a strong call to action that encourages them to subscribe.
5. Create Keyword-Rich Playlists
A keyword-rich playlist gives YouTube deeper information about your video's topic. And like we saw with your description, more text-based content=more views.
Once you have 10 videos in your YouTube channel, organize them into tightly themed playlists..."
Infographic credit (posted in the article): TAG SEO http://www.tagseoblog.com/images2/youtube-video-seo-ranking-factors-infographic.jpg
Via Giuseppe Mauriello