I can't paint a decent butterfly

Maybe pink one fits the class best but I kept trying with all of them. Currently used paper may be not the best for the task but still... why these butterflies keep looking so not_great I have no idea.

Maybe pink one fits the class best but I kept trying with all of them. Currently used paper may be not the best for the task but still... why these butterflies keep looking so not_great I have no idea.