Source: http://www.huffingtonpost.com/sajeel-qureshi/internet-sensations-expla_b_6887226.html
It has to be relatable and consistent.
People inevitably share what “speaks” to them. And when you keep in constant contact, committing to consistent posting, you will naturally produce content that goes viral.
It has to appeal to the masses.
Your material has to appeal to a good number of people; if you’re not targeting the masses, then aim for a specific market. Try to work with a variety of styles and concepts, until you get the right mix that gets an emotion out of your audience.
Be prepared to promote.
No viral content simply “sat” on the Web, waiting to be discovered. You have to persevere and work hard at promoting it. Share to specific people who can promote your content to a massive number of people. Find online communities or people who are talking abut your products and services — and jump right in with your pitch.