Hi Miroslava, Thanks for sharing! I definitely think there's lots of children's books out there that are suitable for this kind of graphic work. The main thing I see here that I think is lacking is composition. It's only four pieces, so it's tough to tell, but the composition on these is basically all the same - that is, everything is centered and near-symmetrical. This will limit you in a portfolio, because subliminally (composition being the thing we all 'read' first about an image), all your images will start blending together. One of my favourite graphic children's book artists is Jon Klassen. His stuff appears so simple (and it is, in a good way) but his sense of composition is fantastic. His style is different from yours, but on the composition level I think it'd be a good idea to look at his work and see what you can gain from his compositions and what makes his pictures feel unique. Another recommendation to look at/study from: Benji Davies, who wrote the Storm Whale series. So much juicy mood and great composition, with such simple forms and shapes. Hope this helps, and keep it up!