The first and the foremost thing you need to do is website audit. Discover any potential issues that your website might have (from a technical, linking, or SEO perspective) and Correct those issues. This will give your website audit score a boost. Then after you can showcase your top 10 traffic-generating blog posts by updating them. To update pages you can re-write your headlines and subheadings, discover and incorporate more relevant keywords and much more. Also don’t forget backlink-building for your top content. The number and quality of backlinks a website has carries a lot of weight with search engine rankings. Therefore start investing in more backlinks on your top posts and pages if you wish to double your website traffic as fast as possible. Don’t forget Google gives priority to good backlinks. So focus on building quality backlinks and not quantity.
Also become active on Quora. You can start writing daily responses to various topics and discussions, comment on others posts that are relevant to the topics you write about, find and exploit questions that are already popular to get more attention to yourself.