I optimized my website the other week. Some things that I did that were relatively easy included: removing Font Awesome (I replaced the relevant icons with SVGs since I was only using a few of them), removing jQuery (replaced with vanilla JS), lots of CSS (removed a lot of cruft from unused rules, etc from my SASS rules), and got rid of as many full size images as possible (replaced with webp thumbnail links). I got the size of my website down to less than 100 kb gzipped for the pages with images and less than 50kb for those without.