How to promote YouTube channel through Instagram and Stumbleupon?

Hey Guys,
I have YouTube channel "The Indian Roar". I create videos related to unknown facts/lesser known facts. I promote my videos on Facebook & Reddit. I want to increase my subscribers and views. Can someone help me with promoting YouTube channel on Instagram & Stumbleupon? Also, Can Pinterest help me in the promotion of my channel?
**I am looking for free stuff and not paid promotion.

Take advantage of email marketing
Promote your YouTube channel on your blog (If you have it)
Run a contest
Include a link to your YouTube channel in your email signature
Teaser out upcoming videos

Share your channel in social bookmark sites, Start a blog for your youtube videos.