1. Those trousers fit you perfectly.
They`re just the right size.
2.This top matches your black trousers.
3. Red suits you.
4. This top doesn`t go with this skirt .
Source: Cambridge Advanced Learner's Dictionary
fit: to be the right size or shape for someone or something
match: If two colours, designs or objects match, they are similar or look attractive together
suit: (usually of a colour or style of clothes) to make someone look more attractive
to go with sth: If one thing goes with another, they suit each other or they look or taste good together