Optimise a Wordpress install on WPEngine and on my own server

I have an existing Wordpress install on WP Engine that I feel is too slow. I want to Optimise it so that it loads much faster. In Parallel I have the identical install on a Digital Ocean Droplet as I am considering moving the website over. I'd like someone who is experienced in these things to take a look at both installs and Optimise them fully so they fly - I want to get 90% at least in Google Page Speed - there will be a bonus $ for higher scores. You can look at the JS, CSS, HTML etc - anything. On the Digital Ocean install I'm happy to consider Server Optimisation (this isn't possible on WP Engine as they dont allow server access). The website must look and feel the same as it does now and still fully function. Milestones are as follows: 10% on starting project +20% on WPEngine Install Optimisation +20% on Digital Ocean Install Optimisation +50% on Completion of project. Please respond with a proposal on how you would approach this, those that do not include a proposal will be ignored - sorry but too many automated bots on here for me to consider, if you take your role on here seriously you wouldn't be using a bot to pitch for you!