- Use a good light source. Fluorescent lighting is the worst. It casts an unnatural light/color. If you have light/fair colored skin, it will also highlight the flaws in your skin and make it look blotchy. Try to find a light source that has "warm" colors and simulates natural sunlight. Of course real sunlight is best. Try outdoors when the sun is at an angle, like between 2pm and 4pm.
- Don't hold the camera too close to your face. It will distort your features. If you're using a camera phone, then holding it at arm's length should be fine. Or if you're using a bathroom/gym mirror, step 2 - 3 feet away from the mirror. Make sure there's good lighting.
- Don't try so hard to strike a pose. Just have a natural or neutral expression on your face. Or try looking away from camera. Or set your camera's self timer and point it towards your face. Then read a random stupid/funny thread in the forums and capture a natural/realistic smile.
- Keep trying. Like Lostboy said, you're gonna snap a lot of pics before you settle on a few.