Children Cardboard Book, Animal Cardboard Book Printing, Printint and design in China
In a good picture book, the child should be surprised and delighted by the variation in the images on successive pages. If the illustrations are too similar from one page to the next, it is perhaps a children's story (that might or might not have illustrations) rather than a picture book.
If you hope to sell your book outside your circle of family and friends, the theme must be universal however localised the characters and settings. The theme of loneliness, for example, can work just as well if the characters are kangaroos, sloths or badgers.
Be clear about whether animals in your stories are actually animals or are people in animal guise. A real horse on its own in a field, for example, may run up and down the fence line when it sees horses galloping in a neighbouring field. But a horse that tells a passing rabbit that it is lonely is actually a human represented as a horse.
Don't be misled into thinking that, because your grandchildren like the story you have written, other children unknown to you will like it, too.