Website speed is a big factor that's related to relevancy. Your site is far more relevant if it loads quickly. To that end, find a good content-delivery network (CDN) you can incorporate such as Amazon's CloudFront or other services. CDNs help to spread your content across servers all over the world and serve them to the nearest visitor. Also, reduce and optimize images and use a service like Oleg Schegolev's SEMRush to help identify performance issues with your site's speed.
Medium is one of my go-to platforms for marketing my content and provides another authority-site domain that gives you the versatility of link-dropping the way that you normally would through any blog post on a CMS like WordPress. Leverage Medium to create intuitive content marketing posts that also link back to your primary posts on your site or blog.
Email marketing is an incredibly useful tool in a variety of ways. It helps you build a stronger relationship with your core audience, and lets you easily market new products or promotions. You can also share news and interesting information with your subscribers, and let them know about new content right away. All of these can have a significant effect on your traffic levels.