What has worked for me for a long time is (only got revo about 2 years ago, though)
1.) ccleaner, ran whenever I remember, using their registry cleaner. Also go to the startup section and remove any processes you don't need
2.) revo to uninstall programs (installing with revo makes this process better because it keeps track of where everything goes instead of playing hide and seek when it scans later)
3.) using good anti-malware to clean your system & browsers
4.) add ons to clean your browsers and protect them from ads & harmful scripts & privacy concerns (browsers can be optimized for safety and performance with add-ons and I reccomend Palemoon! Also there are some good about:config changes, like turning off geolocation and webRTC leaks- check your privacy report at ipleak)
5.) piriform defraggler (sometimes when I run this it clears up quite handful of GB- because Im constantly downloading/deleting/moving around large video files due to my anime addiction
)
6.) organize all your files very well. Use multiple subfolders so you know exactly what is where. This will help you clean and prune your computer so you can clear space more often and find things easier- makes the computer feel fresher. Not typical "optimazation" advice but I feel it optimizes by increasing experience & ease of cleaning tenfold!
Using these six things my PCs have run very fast & snappy with no issues and clutter- for years!