Prepare the wooden surface by sanding it. The coarseness of your sandpaper determines how dark the stain will appear. For example, a 150 or 180-grit sandpaper is very fine, and will not allow the wood to hold much stain -- providing a lighter finish. If you rough up the wood with a coarse sandpaper like 60 or 80-grit, it will hold more stain and allow for a darker finish. Sand in the direction of the wood grain to prevent scratches.
Wipe off any sawdust with a rag or cloth.
Open your can of stain and stir it with a stir stick. Apply the stain by dipping in your brush, then brushing it onto the wood in the direction of the grain. Your strokes should be smooth and even. Blend strokes together before they dry to prevent lap lines.
Wipe up any excess, unabsorbed stain with a dry cloth, wiping in the direction of the wood grain.
Allow the wood to absorb the stain and dry for 24 hours. For a darker finish, apply another layer of stain.