The first step to a good finish is to make sure the surface the finish will be applied to is free of all defects such as dents, gouges, scratches and milling marks.
Most finishes bring out the natural grain and beauty of the wood.
Unfortunately, they may also magnify any defects that may have gone unnoticed. What appears to be a minor defect on raw wood will stand out like a sore thumb when a stain or finish is applied. Surface preparation should begin before the project is assembled. A fair amount of common sense should be used during construction. In general attention to detail such as tight joint lines and excess glue squeeze out should be addressed during construction.