Hey Roman,
Broad question - but this site - MOZ.com is the right place to start looking. The Yoast plugin is good house keeping, so if you are looking for a cooler plugin to give you a bigger lift, I'd say the house is clean enough if you are using it properly.
The next phases are to move through the on-page factors with an audit and make sure things are passing, then consider the off-page work you can do to generate links with guest blogging and general hustle. If you still want to play with the site you can work on building up better taxonomy that matches target keywords to build link relevance and landing pages that structure concepts more. That is how we built up our navigational verticals on WholeWhale.com/resources
Properly configuring Google Search Console through Google Analytics is also a great move to better understand the phrases driving traffic and how they are performing. As you max out the potential of the organic traffic around terms, the next phase is creating better ways to convert that traffic to emails/sales - sumo.com and optimizely.com are interesting tools to do this with.
Forgive the wandering answer, happy to refine if you have specific questions.