Harvey Best replies: I would recommend a light sanding with 180 sandpaper as a preparation for a wash coat of shellac. The shellac I prefer is a one pound cut using super blond flakes dissolved in alcohol; a fresh mix no more than 48 hours old. Using a good China bristle brush I spread the shellac as quickly as possible in the direction of the grain without over-brushing. The blond shellac will highlight the grain without adding significant color.
For filling knots and voids in the surface I try using shellac sticks to blend and fill with a color to match the grain. Follow up with sanding up to 220 grit and top coat with lacquer or polyurethane.
Marty Milkovits replies: Several coats of oil, each given sufficient time to dry and rubbed back will give a depth that cannot be achieved with any top coat.
To enhance the figure, use a light coat of dye and rub back, followed by a top coat. For ease of application, durability and repairability, lacquer is hard to beat. Conversion varnish is extremely durable but is not very forgiving for repairs or touch-ups.