Male characters
Appearance: 16-35 years old; no facial hair; no glasses; eye/hair color can be whichsoever, but more often I prefer types with dark hair and light eye color (with black hair and grey/blue eyes being my fetish); usually prefer tall characters, but average height is okay; clothes must not be feminine and preferably not official, everything else is okay (favorite - jeans and T-shirt).
Personality: smart, strong-willed, kind (but if it's a yandere and other damaged types, then at least kind to the main heroine), forceful but not totally ignoring the heroine's will, resolute, inventive. If he is a smart, sarcastic type, then I will like him almost guaranteed. Also, I like energetic, quick characters, almost can't stand characters who are talking slowly or with some defects.
Female characters
Appearance: I'm okay with any apperance, but if she is at least nice to look at, then all the better. Can barely stand characters who are showing-off their sexuality, though (deep neckline, too short skirt and etc).
Personality: not evil, not nosy, not forceful, not cruel. If smart - then all the better, but if not, then she has to be at least kind and I will like her. I also like tender, softly speaking characters (but not too slowly speaking or stattering). Also, if she is a smart and sarcastic type, then I will enjoy her company to some extent even she is evil, forceful and etc. I just like characters who are fun to watch at.