Spell-check for goodness sake. There is no faster way to look unprofessional than to have "poorgrammer" as part of your title.
Links, and links, and links. Whenever you can - show links to prior work, prior companies, anything to give the reader a better idea of who you are and what you've done.
Be creative with your title. You have about 0.1 seconds to make an impression when your profile first appears in search results. Better have some standout keywords in there. Be creative, be fun, be a "java ninja" or a "php rockstar".
Upload a picture of yourself. While your coding ability may have little to do with your appearance, every buyer I've ever asked has told me that the pictures gain their attention. btw, logos don't have the same effect.
Prove your identity. Check out some of the online tools and sites for getting a stronger online identity. Beenverified.com has an embeddable online ID verification.
Don't forget your keywords. Think as if you were a buyer. You're looking for a professional just like you. What keywords would you use in your search? If you know some unique skills, put them in your profile. It's not going to hurt and it will increase your profile views.
Set reasonable expectations. You may not find Google recruiting at oDesk today , but you may find some outstanding long-term clients. Set the right expectations and the right hourly rates or bids with the right audience in mind.
Stay on top of tech trends. Is Ruby hot right now? Have you been an admin assistant and now you want to do some technical writing? Know what skills are in demand and seek out learning opportunities. It may take you a long time to become an expert, but the rewards could be worth it.
Include testimonials or references. It's nice to read paragraph after paragraph about previous client work that you've done, but a good old fashioned customer testimonial and reference is often the most powerful message on your profile. If you don't have any yet, do a tiny project at a reduced cost to gain the experience and the reference-able customer.