I only tend to remove or move files that are taking up space, or using the disc cleanup tool if you are using Windows.
Disc Cleanup Tool
Click on My computer so you can see your drives. Right click on your C drive and choose properties, then you can click on disc cleanup, in the next window you can choose what windows can clean up for you, you can often clean up old update files or such. That's an easy and safe way to clean up the C drive but it doesn't always clean up a lot.
Removing or moving files that are taking up space manually
I tend to use a free program called Treesize Free, it lists all folders on your drive by size so you can easily clean up space manually. I don't recommend downloading programs that free up space automatically.
