We are a healthcare startup, we focus on content around that but not limited to healthcare. What has worked for us (Doctors' Circle - http://drcl.in ) -
a) Creating videos on topical content, something which is worthy of share and inspires people.
b) Creation is only 30%, 70% is selecting and working on right distribution channel. FB, YouTube, WhatsApp, niche communities, blog etc
c) Most important point that we always keep in mind- Every content video will not hit the mark. Continuous effort towards churning out fresh content is key. Many will fail, few may reach vast audience by accident. This keeps us in pursuit of that viral content.
d) CTA is necessary but should be like salt in a dish or may be like a dessert at the end. We try to do this.
Results- We have not been able to achieve great success such as 1M views but we have seen some good results with 100k+ reach quite a few times. All organic by 1.25 (my time goes on product side too) member team. Traffic on our app page has grown in recent months and also our conversion rates. We can't figure out the exact % of growth that resulted from content marketing but we attribute a decent share of growth to it.