Get someone else to take photos of you. Get the lighting right, either by facing the sun or in a brightly lit room. Also, as far as I know every camera allows you to change the white balance, to get rid of that ugly yellow light from incandescent light bulbs. I also try to stay away from taking photos angled up because that kinda makes you look fat sometimes. Hope this helps :)
I don't understand -- the picture of you on your profile is just some very informal webcam picture, right? Yet you look great there -- beautiful smile, wonderful eyes... you're very attractive in that photograph. Are you saying that most photos don't capture that beauty?
When you're taking a picture tilt your chin down slightly and make sure you're pushing your shoulders back at the same time. It's also important to be thinking about something that makes you feel happy, bad ass, or sexy depending on what you're going for so that emotion shows through your eyes. Also, practice tilting your head slightly at different angles to see what way makes the light hit your face the best. Make sure you aren't leaning forward when you take a picture either, because it will make it look like you're jumping out of the page. If you're going to smile don't smile super huge because it makes you automatically shut your eyes a little more.
Experiment with lighting (natural from the sun, lamps) and angles.