As Joe explained earlier, MP's mostly affect the size of the photo. The biggest improvements you can make when trying to take a still photo with a fairly up to date digital camer is your lighting. I worked with Video and still photography in the army for roughly 5 years, and the thing I hated most about it was spending 3 hours to fix the lighting to do 5 min's worth of shooting. You will probably also notice that on the dials of most of your camera's there are different settings. These are preset's for diffent conditions. They can help make a big difference at times.
If your the type that likes to play with settings and your indoors you can try increasing your exposure time. Only if you can mount your camera to take the photo or the tiny movements from you holding it will blur the image. It works well because it is able to take in more light (Great for indoors where light is usually limited) and it gets more exposure time on the object typically giving you a more indepth photo.