I have a standard jewelers file set and a diamond set. I find the diamond set cuts faster but the standard set cuts a finer line to I often start with the diamond files to set the pattern then finish with the standard to get fine, sharp lines.
You can google "file work on knives", etc. and get a lot of pictures of file work. Lots of great ideas.
Unfortunately it is hard to do file work on a finished, hardened knife steel compared to pre heat treated steel. It takes more effort...sometimes much more effort hehehe.
I suggest you get some mild steel, etc. from a machine shop, etc. and practice.