That central box on the top of the page is the first thing I look at, particularly how she answers the faith questions and age, finally I will look at the About Me and Ideal Match sections. If those catch my eye, I will look at the rest of the profile and see how everything else matches up. I also look at the rest of the pictures.
In the main About Me section, I look particularly for someone who appears to really know herself and what she wants to do in life. She doesn't necessarily need to have everything figured out (there are few of us that do, I think), but I am much more likely to contact someone who has definite goals and aspirations. Someone who recognizes she is human, yet continually strives to draw closer to God. A strong faith is important, and I also look for someone that I believe will be able to walk with me as a partner, but also challenge me to grow. My hope is that my profile reflects these same requirements that I look for in others...
Location doesn't really matter to me. Of course local would be easier, but then again, the Lord never said this whole business of life would be easy, did He? :) I also like it if she has an interview and has taken the temperment test. That shows someone who is serious. I will say that while some commonalities are important, a different temperment or varying tastes aren't deal-breakers for me. In fact, that can even make a person that much more interesting to me! Is that strange?
Red flags - little information, very generic answers, responses that seem incongruous with either the rest of the profile or forum posts, or terrible grammar or spelling. The last one, however, I am willing to pass over because I know there are those out there that have English as a second language.
PS: I'm just being honest - most guys are very visual. While this is not always the case, there are times when I click on a profile due to a picture. As I have personally found since changing my profile picture, it makes a difference!