The easiest way to optimize Windows 10 and give it a bit of boost does not even require you to download any application.
Just click on the Windows start menu button and type sysdm.cpl and run that file.
Click on the tab called Advanced.
Now, start to uncheck all things you think is unnecessary.
This is most usefull for older computers, if you got a fairly new PC you wont see much improvement.
Also, make sure you remove junk files to boost your PC even more.