Blurring the Background
By using a wider aperture you can make your subject standout and look more professional.
Using a DLSR camera, I usually try for an aperture size around f/2.8 to f/5.6. The aperture regulates the amount of light going into the camera and onto the film and affects the field of depth. This will help blur unwanted backgrounds and make your subject stand pop. You can even try experimenting with smaller apertures.
You can also blur the back using photoshop or some other photo editing programs, but doing it while taking the picture is obviously much easier.