In general, I like the cute ones with C or D cups. All depends on what their role is in the game though, there's a lot of 25 year old moms and aunts out there that just seem silly.
Girls get points for traits like...
1. Virgin
2. Cute, sweet
3. Shy but affectionate
4. Flat
5. Short
6. Pale
7. Nerds, wallflowers, freaks or normal girls
There are also negative points for...
1. Sluts, egobitches or snobs
2. Dark skins (no rassism, i just prefer pale white with pink bits)
3. She-Hulks
4. Make-up except for goth style, black is okay ^^
5. Tattoos, piercings, brandings and any other body mods
6. Big tits, fat asses
7. Annoying or incompatible personality
The girls with the most points i hunt down, in games and reality. I dont refuse others, but i dont hunt them myself.
Literally all of them. Even if I don't even like the character, I still do her route. Even characters I'm not very fond of can have good scenes.
But if I had to choose, it would be the most fun one, the girl who talks equally to the main character, is already a friend of his, isn't afraid to take iniciative sometimes (I don't even mind sluttier girls, in fact I find it hotter) and preferably have already a good relationship with him.