One of the least expensive, most effective ways to liven up a drab kitchen is to repaint your kitchen cabinets. Given the dearth of wall space in most kitchens, as well as the general blah-ness of most appliances, changing the appearance of your cabinets can be the best way to brighten and liven up your kitchen.
Your options for repainting cabinets are only limited by your imagination. The simplest thing to do is to paint everything the same color and keep your existing cabinet hardware. But you can also use different colors for the cabinet and frame and even add accent colors if your cabinet doors have inlaid areas. And because you remove the cabinet hardware when you repaint, consider replacing it with something more interesting.
In general you want to use a glossy finish for your cabinets, which is more durable and easier to clean. Using oil-based paint is also a good idea because it cures faster and harder than latex paint.
Assuming you use your kitchen for cooking, the cabinets have accumulated grease and grime over the years. After taking your cabinet doors down, remove the hardware and tape off or remove the hinges, thoroughly clean everything using a strong soap and water solution. And use wood putty to fill in dents or dings.
If you are painting over paint and your cabinets' finish is under eight to 10 years old, you should be able to get away with moderate sanding. If you are painting over a different type of finish or a finish that is more than a decade old, sand down to bare wood. A 120-grit sandpaper should be sufficient. Follow with 180-grit if you want a particularly smooth finish.
Use a cloth dampened with mineral spirits to get rid of the wood dust. When everything is dry, use a coat of primer. Consider using a stain blocking primer because residual stains are likely the result of grease or oil, which bleeds through ordinary primers.
Professionals use sprayers to paint kitchen cabinets. But they know how to use sprayers. Unless you have experience using paint sprayers, you're better off using a high quality natural bristle brush to apply your oil-based paint. You still end up with an outstanding finish.
In deciding how many coats to apply, remember that more paint equals more durability. In general you want at least two coats of paint. If you tend to beat up your cabinets, or they're badly stained, or you're going from a dark color to a lighter one, go with three coats. Make sure you allow each coat of paint to dry completely before putting on the next coat.
Lastly, give the new paint time to reach maximum hardness before installing the hardware and putting the doors back in place. Doing so ensures that your cabinets' new finish keeps looking new for years to come.