Def. clean up (AKA delete) any files under users\<you|anybody>\AppData\Local\Temp, often a few GBs rack up there. Often one or two files will be in-use/locked, but you can blow away the rest.
Also, temporary internet files can build up over time, I recently removed a bunch of them dated 2010-2013 (?!) which amounted to another couple of GBs. c:\users\<you|Default|anybody>\AppData\Local\Microsoft\Windows for the IE temporary internet files folder, not sure about Mozilla/Chrome/Opera etc. (simple enough to search).
Regarding the Windows.old folder, I believe that Windows cleans this up after a month of so of it hanging around, it's the OS which you upgraded from. You could always back it up in case you want to go back to the previous version of Windows.
Pretty much all installers leave tons of guff hanging around in the system registry, you can free up some space by running a decent registry cleaner against it. I think CCleaner is about £20.
Another thing worth checking is the location/size of the swap and hibernation files (pagefile.sys, hiberfil.sys). I believe that you have some control over the size & location of the swapfile and possibly the location of the hibernation file. This can also help to free up q. a bit of space.
Also, check your downloads folder, this can often get rather large.
HTH :-)
p.s. I only have 17 C++ redistributable packages installed, but I do have 34 separate M$ SQL Server packages installed - go me!
I guess they'll come in handy if I ever actually use SQL Server..?!