Improve a WordPress site

I have a WP site which is working. You are requested to first audit it and then edit the code accordingly, mainly for: - Increase the loading speed (optimize the database code) - Check the functionality and correct possible flaws for: registration of new records, searching the site, displaying the search results. - Improve the design of some local elements like click buttons (size, color, moth over effect), etc. - Admin login to work properly, etc. - Bring other improvements / enhancements / tuning up, as considered necessary by a professional. Notes: - Required knowledge: WordPress, PHP. Must have much previous experience with WP. - Automatic bids will not be considered.