Personally, as a straight woman, I find myself most drawn to female characters who are very beautiful but not overly-sexualized. My personal favorite female character designs are tall, lithe, feminine, GORGEOUS long and thick hair, mature. The face, especially, is unmistakably adult. Long with a high nose bridge. Beautiful instead of cute. I think Leiji Matsumoto draws some of the most enchanting women.
Here are some examples of other female character designs I like (although many are not from sources that are appealing to women, and may be very sexualized within their media, I still think their character designs alone are very appealing).
Now, making male characters that are attractive to women, that's a very interesting subject indeed. What men and women find attractive in men are very different.
In terms of faces, men typically are attracted to very masculine, rough, square, chiseled types of faces.
This is NOT a popular face among women, however. I've found that the best way to attract female audiences is to go down two separate paths:
1.) Make him a bishounen/pretty boy/ikemen. Make him prettier, cuter, softer. Look at all of the anime guys women are into. Give his face some vulnerable charm, some feminine balance and youth. Another important component to the pretty boy formula: GOOD HAIR. Women love a nice, healthy head of hair.
2.) Obscure his face. Make him a masked character or make him inhuman (deformed or disfigured, even). You can typically make a character who is otherwise very big, masculine, scary, but if he is in some way "faceless", he can attract female fans. Think of Ghost from CoD. Think of Venom. Hell, think of all the weird TSM blorbos with fangirls like Sans, Spamton, or Bill Cipher.
Actually Beauty and the Beast is a good thing to go over. Usually people focus on the archetypes of Beauty and Beast, but instead think about Gaston and Beast as archetypes for the male ideal from a man's perspective and a woman's perspective. Men like Gaston and women like Beast.
Both 1 and 2 also help make the character visually interesting and distinctive rather than falling into "nondescript, generic male protagonist" territory.
In terms of the body, women either like guys who are quite slim, as you see with anime characters, or they like guys with leaner muscle. Even women into very muscular characters tend to like them configured in a different way than men. From what I've seen, men tend to be the most drawn to male characters with really big upper bodies, and pay less attention to the rest. They look very wide. The Johnny Bravo type if you will. Women want to see balance and definition in the legs as well. Tall, with broad shoulders tapering to a little waist and then nice thighs and butt bring everything into harmony. If you look at fanart drawn by guys and compare it to fanart drawn by women, you can see men tend to be really into the amount of muscle (more is more) and they like a lot of vascularity, hard shadows, sharp edges. Women are more into overall form, shape, flow, and don't like as much vascularity or striation. Compare the difference between Goku and Gojo in terms of male and female fanfare.
And, of course, if you frame your male characters in ways that are obviously meant to be fan service for women, this is going to put off men. So that's kind of a sure-fire way attract mostly women.