Assuming you are not a student of Fashion Designing programme. You need to first know what all aspects are part of fashion. Fashion is a very wide industry and there is huge scope to grow in this industry. You need to study on which part you want to learn more. If you are good at illustrating, you can look into more of illustration related books or online like pinterest and improve your skills. If you are good at writing about fashion and accessories or are knowledgeable of world over trends you can opt for fashion communication. There are so many resources to learn fashion designing like online videos, articles, Blogs, tutorials etc. But I would suggest you to choose the option with the systamatic study whether your Degree or Diploma programme.

Good Luck!