Completing Your Profile, Part 1—The Picture
Your picture is the most important part of your profile on whatever site you select. Most of the relationships we eventually forge are based on the shallows of physical attraction; the decision to click a mouse is exclusively driven by the picture the cursor is hovering over.
You can use as old a picture as you like, if you never plan to actually meet anyone. Other than that, stick within the last few years. You look almost as good as you did two years ago. You don't look as good as you did ten years ago.
You can go blurry—many people do. Again, unless your first date will be the two of you talking through the porthole on a diving bell, blurry can backfire.
Posting a picture with more than one person in it. This happens, too. Most of the time people will be able to figure out which one is you, but it's distracting, especially if the other person in the picture, by dint of good genes or just lack of aging, looks far better than you do. Never post a picture of yourself in an embrace with an attractive person of the sex you are trying to attract. If it's a great picture of you, crop them out. Many of the profile pictures you'll see are being held by disembodied arms or rest their heads on parts of shoulders. If you feel guilty about cropping them out of your life forever, you probably shouldn't have broken up with them.
If you’re the viewer, don't complain about the disembodied arm, or ask whom it belongs to. This just exposes your jealous, insecure nature.
All the sites allow you to post other pictures besides your main one. This is where people post pics of their children, pets, cars, boats, Harleys, skydiving instructors etc. If you have other flattering pictures of yourself, post them here. Nobody cares about any of those other things, except maybe the Harley. There is an entire subcategory of women that "want to ride on the back of your Harley." Nobody wants to ride on the back of your Kawasaki, so don't bother mentioning it.