Speedtest of Prestashop page as fast as possible can

We need to improve conversions by doing our Prestashop 1.7.1 page as fast as we possible can. This includes photo quality review, conversion of phrographs, disabling modules in some parts of the web are not needed (this part is very delicated as some of them are custom modules), and every other needed task to assure webpage is very very fast. We have a powerful dedicated server so this should not be a problem.

Also, we would need a document explaining (if any) which recurrent tasks we should do in order the page is not slow in some time.