Network with others on YouTube and on here, by network I am talking about talking to them, getting to know them and the progressing on to working with them doing collaborations. Other than that theres sharing your videos here regularly, sharing them on Facebook, Twitter and the other social media sites, some are more dead than the others though. You could try a giveaway if thats up your street, they get a lot of attention if the thing youre giving away is good. Make good videos too to the best of your ability, it all depends on your market though, think about who will be wanting to watch your videos and make your content for that group of people, its must easier than going for everyone in general and technically much more profitable if you ever wanted to monetise your videos.