You have to be prepared to fail when it comes to creating a successful viral content campaign. This is one of the greatest marketing strategies and once you get it then the momentum just keeps going.
I've seen people come up with crazy formulas for creating viral content but I don't believe there's a formula, it's always trial and error. The stuff that I share that goes viral helps/boosts the other stuff that failed to go viral, so you just have to keep going.
I never try to reinvent the wheel, what I mean is, I simply go where things go viral and see if there's anything related to my niche then snatch it, make it as original as I can then share it with my audience.
Places where things go viral? Tumblr & Reddit, that's where most people find viral content.
Things go viral pretty easy on these sites, I don't know any other online portal where things go viral like on tumblr, things get reblogged/liked pretty easy just as long as it's worth sharing. You can also get some good nuggets by simply browsing your google+, facebook or twitter feed sometimes.
The only difference is that on tumblr, reddit and pinterest some people don't even use their real names so nothing is personal. The problem with other networks is that you have your family, friends, colleagues, neighbors etc. in there so it becomes too personal.
What I mean is people are uptight on facebook & twitter but on these other networks it's a circus, people let lose and share what they'll never share on FB. Something that goes viral on tumblr can easily go viral on these other social networks.
Basically, find something that has a track record of going viral and make it as original as you can. If you can't make it original then give credit where it's due. Feel free to go fully original as well, I do it most of the time and it works.
Hope that answers your question.