When it comes to character, In my opinion you can always determine the illustrative style by what type of eyes the character has. Manga characters are a perfect example of this as their eyes are a dead give away as to what style they are drawn in. Another is the style in which Disney characters are drawn in they always have big beautiful eyes with a lot of detail.
I wanted to steer clear of both of these styles as I was not going for a Manga style in my book and I am desperately trying to get away from a Disney inspired illustration due to the first phase of the project. I thought the best possible way to do this was to just quickly hand draw a lot of different eyes in different styles. This is exactly what I did and I drew eyes of all styles even Manga and Disney to see if I could manipulate them into anything more unique.