Try Different Angles and Lighting
Don't just snap a photo with your cell phone and upload it without any further thought. Take multiple pictures with a variety of angles and lighting. Try standing at a 45-degree angle from the camera if you want to appear slimmer. Place both hands on one hip, a hand on each hip or both hands crossed in front of you for different looks.
As for lighting, a natural, soft source is your best option. Hard lighting, such as from direct sunlight or a bright lamp causes shadows that will hide your face, may trigger squinting and accentuates blemishes and lines on your face. Ideal sources of soft lighting include shooting outdoors on an overcast day or sitting near a window on the north or south side of your home.
Backgrounds and Surroundings
The best background for your profile photo depends on your personality and the purpose of the photo. If you are creating your profile on a dating site, you can incorporate a passion such as rafting on a white river or playing the cello onstage. For a professional profile you might want to stick with a simpler background such as a neutral wall. Of course, if cello playing pertains to your professional life, then the stage is perfectly suitable for a work-related profile pic. While lush landscapes and interesting architecture can add flair to your photo, be sure that the background does not take the focus from you.
Similar to profile photo tips on choosing a background, save the pictures of you and your buddies for your photo album. People viewing your profile may be confused if there are several people in your profile pic, and a potential employer might be turned off by the shot of you and your jealous-looking significant other ("If I hire him, will she be phoning every 15 minutes?").
Avoid standing in front of your bathroom mirror holding your camera at an odd angle or stretching your arm out in front of you to snap your photo with your cell phone. Bathroom lighting is generally unflattering, and it is difficult to look confident and poised while straining your arm and trying to find a good angle. If you aren't able to get someone to take some shots of you, invest in a tripod and utilize your camera's timer settings.
Relax and Smile
Perhaps most important of all the profile photo tips available, nobody looks good with a "duck face." Although popular, the pouty, pursed-lipped pose is neither appealing nor professional.
Everyone looks their best wearing a natural smile. Whether you prefer toothy grin or a muted, closed-mouth version, smiles makes you more attractive. This is true in the dating world, in friendship and in business. A smile displays friendliness and approachability. Smiles are infectious, as well, which means that those viewing your profile will feel happier and relate that feeling to you.
Finally, smile to leave a lasting impression. People have a greater tendency to remember someone with a smile than someone without one, so think of a happy thought and say, "Cheese!"
Hard Lighting: sxc.hu/Jason Nelson
Couple: sxc.hu/Bina Sveda
Mirror: Flickr Creative Commons/benfu