Videos are particularly well-positioned to go viral, so what you want is to make sure that:
(i) you're promoting your videos on social channels: YouTube and Twitter are the primary ones. Don't be afraid to post a video to Twitter and ask for a "RT if you think this is funny!" People will do this, and it can quickly go viral. (for tips on what to Tweet, study copywriting for an evening; the key is to be compelling in 140 characters, and it takes practice)
(ii) you're watermarking your videos so that wherever your video is shown, it includes a link back to your site
(iii) you're optimizing your videos for SEO. SEO for videos is generally easier than SEO for sites, but that's not to say that it's easy. There are some basics that you'll want to do, and then you should also search around for tips on best practices for video SEO.