The themes of adult coloring books are usually intricate and centered more around adult images, not your childhood counterparts that included bunnies, super heroes, and farm animals. You would expect to see geometric patterns, psychedelic patterns reminiscent of doodle art type pages, fantasy images including angels, dragons, goddesses and mermaids, and ancient designs of religious and spiritual nature.
Determine your childs level when it comes to coloring. Some color books provide large coloring spaces making it easier for children to color the page, stay in the lines, etc. As the child gets older, their skill level for coloring increases as well, and the difficulty of the book may as well. Some coloring books come with written instructions, and other games, such as a dot to dot, or a maze. If you want to keep your child happy, and still challenge them, choose coloring or activity books in their range or level, and do not frustrate them with books that have too small of pictures, or too many spaces to color, or written instructions.
Coloring books generally have a theme of sorts. It might be that they are based on a Disney movie, or it is about animals, or vehicles, or something else. When selecting books for your children, remember that they will want to express their creativity, and will have a lot of fun with any coloring book, but will be more interested in a coloring booklet with a theme that appeals to them. Choose a color book that features their favorite characters, or the item of interest in their life. For example, if your little boy just loves trains, get a Thomas the Train coloring book. If your little girl is as girly as they come, look for the Disney Princess coloring book, or possibly Strawberry Shortcake.