What is the difference between staining and varnishing wood?
Staining will add color and varnishing is to protect. If you add varnish to wood it will darken the wood due to the fact that you are wetting the wood. I would suggest using a sanding sealer to seal the wood before applying varnish. Apply the sanding sealer in very light coats, I always spray it on. Then sand very lightly and reapply slightly heavier coat. Sand again then apply the varnish. Make sure the sanding sealer has the same base as your varnish. Here is a little video to give you some ideas: http://www.easy2diy.
