Most Helpful Girl
I think you could develop a sense of fashion from reading fashion magazines?
Though u may not be interested or think high fashion (e. g. vogue/ elle) are a bit too much to carry and afford, u start to get the sense when u read more.
If u don't want to spend money, there's plenty of fashion blog on the internet, the one I really like is "Lookbook. nu"? Its always shows all the fashion bloggers around the world, so u could follow the ones u like :)