A sharp file is a wonderful thing good for all kinds of work and it’s amazing how precision you can be with a little practice. However, most people haven’t been shown how to use one correctly and they can basically turn your nice new file into a paperweight in minutes.
Pro tip: If you spend a couple bucks on a nice new rasp or file, don’t tell anyone so they don’t ask to borrow it. It’s kinda like hiding your food after the zombies come so your neighbors don’t try to take it.
Mrpete222 has about 1.7 million full length videos on all manner of shop techniques going from very basic stuff to pretty complicated machining operations. Check out his page because he’s a cool old guy. Here’s his videos on files and how to properly use and care for them. In the first video, he goes over nomenclature and the different types of files and I would encourage you to watch all of both videos but should you be pressed for time, you can jump to where he starts showing actual uses and techniques in the second video.
Part the second: