That's a difficult one. Here's what I would look at...

- Keyword research. What are people looking for.

- Content marketing i.e. blog posts, tutorials

- Google Ads

- A free widget, something to attract links.

- Cross posting interesting content to subreddits i.e. design

- Youtube - creating content or sponsoring content.

- Outreach - depends on your market but maybe linkedin.

- Buying high traffic websites and integrating the content into your own site.