Make sure you light is Adequate (if possible don't us a flash).
Step3
Look trough the viewer or on the screen, and.... picture what you are looking at as if it were in a frame already. Would you put what you see on the display or in the viewer in to a frame and hang it on the wall for everyone to see? If yes, then take the picture, if no, then adjust your camera or subject until you can answer yes to that question? Don't be afraid to take more than one picture of the same subject.
Tips & Warnings
Now, after you have taken the perfect picture you may need to do some minor adjustments on you favorite photo editing program. A slight crop, adjustment of contrast and brightness, and maybe a little color saturation you will end up with a wonderful photo.