I particularly liked the illustration below as the expression is incredibly explicit and is a similar style to the type of eye I would like to illustrate for my poster. I think the textures and simplistic shading really works for this illustration as it is incredibly slick.
I think this kind of expression would also look really successful for my poster as it gives off the feel of mischief, guilt and cunning.
Cranio is a vector illustrator and graphic designer from Valencia, who works as a freelance artist. He has worked for many big clients, such as Warner Bros and Nike. His other illustrations are incredibly clean and slick, and I think they're really effective as they generally use around 2-3 colours (which is perfect inspiration for the poster I plan on designing). Some of his illustrations are quite psychadelic, such as his design of Thom Yorke from Radiohead, and a t-shirt designed entitled "Out Come The Wolves".