Paint the desk. You may not be able to customize an office desk, but you can paint a wooden one at home in a weekend. Pick a color that matches the room's decor, and cover up any nicks or scratches the old desk may have. Sand the desk thoroughly to remove old paint or stain before painting. If you don't want to paint the entire desk, consider adding splashes of color to desk drawers or painting a border around the desk top.
Clear the clutter on the desk. A lot of useless papers and baubles will make any desk look junky. Throw out any unnecessary papers or receipts, and put away paper weights, extra pens or rubber bands and paper clips.
Purchase a decorative desk set to hold pens, business cards or calendar pads. Not only are these sets useful, they will make your desk look more attractive. Leather desk sets look especially dressy and classy.
Set out one or two photos. They should be in decorative frames and depicting a loved one, pet or favorite locale.
Add a plant to the corner of your desk. If you have a difficult time keeping a plant alive, use an artificial one. Not only will it dress up your desk, it may help lift your mood.
Ditch the office lamp, and use a dressier tabletop lamp you can find in a living room. Use one that matches your room decor.