You might want to post it on social networking sites for your real friends to see, tell your friends to watch, rate 5/5 and subscribe, advertise them on popular websites, add a large variety of search tags that allow a larger filter variety, etc.
Thats basially what it means, if someone likes your videos and wants to see more of them, they will generall subscribe. However it might take a long time seeing as youtube is such a large site with millions of uploaders. Just keep making vids people like and im sure they will subscribe.