I've experimented around with this quite a bit - below are some of my conclusions.
Title tags and descriptions are quite important. Use the "auto complete" suggestions to help assist with your keyword phrases and descriptions. Use all of the "characters" allowed. For example, you are allowed 5,000 characters for the description - use it!
Obviously, creating good quality videos with useful or entertaining information is critical. Even if you get your video to show up on the first page, people will still need to be compelled to watch it. Keep it short!
Give YouTube context in which your video should be viewed. If your video is about learning how to play the piano. Subscribe, like comment on other relevant videos. Doing so gives YouTube added insight about your video. Be active and authentic.
Good luck!