[SeijiSensei]

I'd point to the difference in the character of two current female leads, Chihaya in Chihayafuru and Kotoura in Kotoura-san, as representative of a non-moe and a moe character. Chihaya is strong-willed, even obsessive when it comes to the card game she plays called karuta. Despite her youth and physical beauty, she does not elicit from the viewer a desire to protect her. That isn't too surprising since she is the heroine of a josei manga, and now anime series, written by a woman primarily intended for an audience of older teen and young adult women.

Kotoura, in contrast, is drawn in the cute style with a wide face much like Hiro in Hidamari Sketch or Madoka in Madoka Magica. For reasons the story makes clear from the outset, she has been an outcast for much of her life. Those experiences helped her develop a strong personality, but she also elicits strong feelings of protectiveness in both the other characters and in the audience as well. This show is derived from a 4-koma comic strip that looks to be part of a shounen manga and thus intended for a male audience.

It is certainly possible to have both male and female moe characters, and a mix of moe and non-moe characters within the same show. Chihayafuru has two supporting characters, one of each gender, who might be seen as moe. Kotoura-san has female characters who definitely do not elicit a moe feeling. In Tokyo Magnitude 8.0, I'd classify the girl Mirai as not-moe, but her younger brother Yuuki definitely is.

Sometimes the style of drawing can matter even within a single show. The third episode of Noein, a show with a wide variety of episode directors, portrayed all the characters, males and females, in a softer and prettier style than most of the other episodes did. It became somewhat notorious as the "moe episode" of that series.