First of all do an SEO audit by yourself or try some paid tools like Alexa SEO audit.

Based upon audit report invest your money where you lag. Backlinks and On Page SEO settings are thing where most people lack.

Backlinks are highly important to rank. So try to hire quality writers and try to post some guest post on various blogs related to your niche.

Invest few amount of money and time in improving on page SEO parameters of your site.