When it comes to video optimization on YouTube, your Title comes first and foremost. But second, make sure you focus on your description.
It’s best to follow YouTube’s guidelines of one to two sentences. Be sure to include your target keywords, but as usual, do not keyword stuff. A good rule of thumb is to use complete sentences. If you just list off multiple variations of your keywords, you will get your video penalized.
Beneath your short, targeted description, feel free to include contact information or links to your other properties. Since these are not keywords, you can feel free to list them. See this videos description for an example of how this can be done.