There are loads of different ways to wear a belt, for boys and girls. There are also lots of different styles of belts. Belts also go with different aesthetics.
A turquoise dress accompanied with a gold or silver belt is sure to look amazing or a white tee and some denim shorts with a clear or holographic belt looks perfect. Really belts can go perfectly with almost anything.
If you are planning on wearing a dress then consider a very thin belt. In summer, when everyone is wearing shorts a holographic or clear belt is perfect. Wearing a hoodie then maybe consider putting on a cheetah pattern or a thin one.