My experience has been this: Guys are very visual so a great picture (but accurate picture) is important. In fact a few pictures that show your face and then full-length that show your figure, well those get a guy going. Also, do NOT post pictures that do not represent how you look now. Nothing worse than going on that first date to only find that the person has gained weight or that they just do not look as good as their pictures. The date will end quickly, perhaps awkwardly, and you will get frustrated. Guys misrepresent themselves too and in the end physical attraction is important as well as honesty so I don't get why people do this.
As far as what your profile says, keep it simple. I found that by putting something simple that represents your personality is the best way to go. I am not a believer of putting your life story down (then what will you have to talk about later) or putting down all the things you expect from the guy. It makes you sound boring or demanding. You can filter through the guys that contact you anyways and you need to spend time getting to know each other through e-mails, calls and dates. Profiles are for getting initial interest not for speeding through the process of learning about each other.
dating sites require more direct communication than many women are accustomed to.
here's how you catch a guy's interest on a dating site. make sure your photos show your body. if a women only has face closeups, I rarely write her. not because she's possibly overweight, but because she's hiding something. and if she's hiding something as important as her body, I wonder what else she'll conceal from me.
otherwise, simply write to his profile. show an interest in the things he wrote about so he knows you actually read how he likes Dean Koontz books and scuba diving. I hate when I get form letter messages about what a great guy I am, but that fail to mention _why_ they think we might be a match.
write to him. show an interest, ask a few questions and say that you hope to talk to him again.
you won't sound like you're begging unless you beg :)
that's it. show your body in the photos, and send a message. the next step is up to him.
bend the truth...u wanna make it sound like ur not boring to be with (even if you actually are) because all that matters is that what ever were doing, is that were doing it w/you. ya know? but in order to attract a guy, you wanna make it look like you're probably fun to be with. people are attracted to energy, and that's what you wanna perceive