Is it mobile friendly? (Google ranks you higher, lower CTR, over 50% of all searches). Is it optimised for Google to be able to read and correctly rank (tags, structure, etc.). Is the user experience logical? Is it geared towards goal completion on every page? Do you require an eCommerce solution? Is your current solution working 100%?
You need to keep your site fresh on a regular basis with refresh articles, blogs and case studies. The more good content you add to your website the more authority you have. You are the expert, you know your product/service best.