Lay down plastic drop cloths and set your project piece in the center. Open windows and doors and set up a fan or two to create ventilation, or work outside.
Sand the surface with a power sander and 150-grit sandpaper. Wipe the dust from the project surface with a tack cloth.
Shake the can of varnish well for at least one minute. Open the top and dip the tip of a fine bristle, soft paintbrush into the varnish about 1 inch. Drag excess varnish off the brush on the lip of the can.
Apply varnish starting along one long edge of the project. Brush varnish onto all edges of the project piece, and into any hard-to-reach areas.
Spread varnish over the remaining surface area. Work in long straight, overlapping strokes to ensure proper coverage. Spread the finish as evenly as possible to prevent runs and drips in the finish.
Allow the finish to set for the time recommended on the label instructions between coats. This will vary from 45 minutes to several hours. Follow the instructions for best results.
Apply a second coat of varnish over the first, working in the same way. Avoid dragging back over the surface with the brush to prevent leaving permanent brush strokes in the finish. Cover the entire surface evenly for smooth, even color. Allow the varnish to set overnight before using the object.
Clean brushes with acetone and store remaining varnish in a cool, dry place, with the lid firmly closed. Fold drop cloths with the varnish side in, to prevent transferring stain onto surrounding surfaces.