As of September 2014, YouTube's own keyword tool stopped working. It was moved over to Display Planner's AdWords video keyword suggestions. To use it, you need to have an Google Ads account. Just like the non-existent YouTube keyword tool, it was created to facilitate paid video and ads promotion. Which is why keywords that you will find there might not be closely related to the topic that you want to cover.
The first is that viewer attention spans- and loyalty- are a bitch. I’m even lumping in my own impatience online here; as a user, if I click to watch a tutorial, an ad pops up, and I see a similar tutorial in the “You May Also Like This” feed, I’ll give that one a shot instead. I’m not kidding. I’ve done this twice today. You don’t want to do anything that will cause viewers to lose interest in your video, or worse, to click to a competitor’s video instead.