One additional, powerful way to gain inbound links on YouTube is to have a friend mention you in a video and link to you in the description. Occasionally, established, more popular users will upload thank you, or shout-out, videos. They'll want to share new channels with their subscribers. Depending on the audience of the person uploading the shout-out video, this could be a big break for your channel.
As you interact and upload your own videos, you will naturally make a few friends who enjoy your sense of humor, editing style, or lifestyle. If one of these friends happens to have a lot more subscribers than you or blows up after being featured, their shout-out video mentioning you can gain you thousands of subscribers. But don't make videos for the sake of getting someone's attention.
At the end of the day, remember to be yourself. Your audience will get comfortable with you, your sense of humor, and your video-making style. That's not to say they won't enjoy seeing you branch out and try something new, but if you get caught up in trying to make videos to please them instead of pleasing yourself, they'll know.
If you do try something different and it does well, resist the temptation to make "sequels" or to make a series. A lot of us have failed to take this advice to heart, myself included. The problem with a series, though, is that formats get boring very quickly. Look at why we have all stopped watching so much TV. Formats are predictable and unexciting. So, unless you are overflowing with the talent required for sustaining a series via great writing and great acting, your subscribers will soon stop watching. And by the time you get bored, eight sequels down the line, and move on to making more original videos, you will already have lost a number of subscribers.