Refinish the tub, toilet and sink. If you have hard water, or if the surface of the porcelain is looking dull, you can refinish these items with a little drywall sandpaper. Use a strip of this special sandpaper and scrub off the hard water stains. Do not add water during this process. You will end up with tiny black flecks everywhere -- that's normal. Wait until the entire area has been cleaned before you rinse it off. Drywall sandpaper is fine enough that it will not scratch porcelain, but it will remove these unsightly stains.
Add a new backerboard behind the tub or shower. Instead of expensive ceramic tile that can also be difficult to install, use a backerboard instead. This board can be purchased at a local hardware store, cut to size and attached to the wall with adhesive. Backerboard comes in many different styles and many look like ceramic tile, but without the high price tag. One sheet of backerboard that is 4 feet by 8 feet is typically priced less than $30, as of October 2011.
Paint the walls and the vanity. A fresh coat of paint on the walls goes a long way toward improving a bathroom. Choose a color that is appropriate for the size of the space. Smaller spaces need light colors, while larger spaces can handle darker colors. Paint the vanity, or if you prefer, sand it down and stain it a different color.
Redo the flooring. Vinyl peel-and-stick tiles are simple to install and they are very low in cost compared to traditional flooring. These tiles can be cut to fit around fixtures with a box cutter and require no flooring experience to install. They can be placed over wood subflooring, or existing vinyl or linoleum flooring.
Change out the existing towel racks. New towel racks, toilet paper holders and other accessories can have a dramatic effect on a bathroom, even though they aren't very large. Select accessories that match your current decor preferences. Remove the old racks and screw in the new racks and accessories.