I totally agree, this is the first thing I learnt and I put it down to my fast growth, when I do a search I always find my videos quickly. From what I've read, your allowed 500 characters, that makes for a lot of good tagging including long tail keywords.
Be more loose when commentating on videos. A lot of the times it's not about what you're saying that isn't getting across it's about how you're saying it. Monotone and stiff inflections are hard to get through especially in a video.