This story shows how to stain and varnish trim.
Staining and varnishing require different techniques than painting. To start with, you can apply most stains with either a brush or a cloth. First lay a coat of stain on the wood in the direction of the grain. If the stain is not working its way into the grain, brush it across the grain and finish with brushstrokes parallel to the grain. It may look muddy at first -- but that will clear up when you wipe off the excess. If it's too light, repeat the steps. For a light tone, first seal the wood with a prepared wood conditioner.
When you apply any clear finish to wood, start at one edge of the piece and work in the direction of the grain. Smooth out any ridges and pools in the finish while it's still wet. Finishes such as shellac and water-base varnish dry quickly, so you have to work quickly.
For greater visual appeal and durability, apply several coats of clear finish, rubbing with #0000 steel wool or very fine finishing sandpaper between each coat.