I use a chain saw raker file. file back to front getting two blades at once, using the "countdown" method. Also getting lighter as you go so that at the end it is just the weight of the file.
Then, using the smooth edge of the raker file (no "teeth" on the edge of a raker file) I steel the edge just like you would a butcher knife. Back to front.
Shaving sharp in no time, and all with one tool that is easy to find nearly anywhere and not expensive.
It is a good idea to put a wood handle on the raker file to keep your fingers out of harm's way.