Add relevant keywords with search volume

Use the YouTube’s Search Suggest feature. All you need to do is:
Head over to YouTube and pop in a word or phrase and YouTube will hand you a bunch of keywords related to what you typed in. These suggested keywords are GREAT.
Why? Because these are terms that people actually type into YouTube. So there’s no need to wonder if they are popular or not. If YouTube suggests them to you, they 1000% are. You can also go to a popular video in your niche… and copy the same keywords that video is optimized around.