Apply pressure as you push the sharpening device down the blade. Only file in one direction. Repeat the motion along the entire length of the blade. Blades are properly sharpened when they can cut paper. Protect wooden handles on tools as well.
Moisture can cause splitting and splintering if it works into the handle.
Wipe the handles with boiled linseed oil. Warming the oil helps it to better penetrate the wood. Be careful not to pile used rags that have been soaked in linseed oil together as they may self-combust. Check tools for loose screws, nuts or bolts and tighten them accordingly. Oil all pivot points and springs.