A set of needle files will work fine. A good 6-8" tri-corner file is also useful.
Some tips;
Sand the spine flat and smooth to 400 grit.
Clean it off with acetone, and mark across it with a fine tip Sharpie marker to make it into square grids. If the blade is distally tapered, these squares will get smaller as the blade gets thinner toward the tip.
Use a three corner file to lightly mark each black line. File deep enough to make a line, but not a deep cut.
Wipe of any remaining Sharpie ink with acetone. The spine should look like a ladder. Use this grid pattern to file the pattern you wish. Any remnant of these marks will be removed when you sand the spine after finishing the file work.
When all filing is done. fold or wrap a piece of sandpaper and smooth up the cuts (if needed), then hand sand the spine to make the surface smooth. A few small slip stones ( used for sharpening woodcarving gouges) ,or EDM stones, will really speed up the final sanding. If you filed carefully, and used a fine cut file, sanding in the tight places is usually not needed.
If you use a buffer ( not recommended for most new makers) buff the file work with medium grit compound. A bristle wheel in a Dremel tool is also a good safe way to buff the file work smooth.
There are several good tutorials on filing patterns like "Rope", "Vine", and "Vine and Thorns" available...some in the stickies.
