There are ways you could prepare good cakes which everyone would love. Adults like themes like a diary, a champagne bottle, or things which depict a favorite sports character. Therefore, cakes for adults do not need to be that vibrant. You may just have something simple with the name and good wishes of the person written on it. In the case of cakes for kids, you should consider what kids generally like. In the case of birthday parties for children, you could have designs showing baby blocks, puppies, teddy bears, blue skies, flowers, yellow ducks and the like.
A popular theme that works well for either a boy or a girl is a clown or other circus_related cake. They are usually very bright and colorful, which makes for instant attraction and a great focal point for a party table.