In winter, you want to look stylish but still keep your body warm. You may never fail with a great comfy layered sweater for formal look. It is based on how formal you would like to look. Black shoes are strongly recommended since they match almost who has any sweater. You can also try leather jacket for informal look but still look stylish.
In any formal look, knit sweater will make you neat and eye catching. Add some long coat as its outer to make you warmer. As for teens, try to wear hoodies and beanies for casual look. Those outfit will make you look cute and handsome.