Hi Pranjal, 

To be a good blogger, you must be a good writer. Someone who can express with words, make a connection with its readers by proving them information, facts, and engage with them through stories and personal experiences. A similar thing is what needs to be done by a fashion blogger. They must be able to inform readers about the latest trends/news in the fashion industry. Inspire them with words. And to do this, it is not necessary to be a part of the fashion industry, by pursuing a course. If you have a passion for fashion, you can be a fashion blogger. 

Although, if you need to learn more about writing styles and techniques, you can pursue a certificate or diploma course in Creative Writing/Feature writing (also includes other means writing techniques). Some institutes are,

1. The British Council located in all metro cities in India offers degree, diploma and certificate courses in Creative writing.

2. The JNU (Jawaharlal Nehru University) in New Delhi offers creative writing as an optional subject in its MA (English) course (if you wish to pursue such programme)

3. Calcutta University offers a Diploma course in Creative Writing

4. Bharatiya Vidya Bhavan in New Delhi offers a Postgraduate Diploma course in Creative Writing

5. Xavier’s Mumbai Central Institute of Indian Languages, Karnataka

6. Center for Research in Art of Film and Television, Delhi which offers a one-year diploma course

7. Indira Gandhi National Open University, New Delhi which offers a PG diploma in Creative writing  the distance learning program

8. U.P.Rajarshi Tandon Open University, Allahabad offers diploma courses through the distance mode

9.  Babasaheb Ambedkar Open University, Ahmedabad

10. The Karnataka State Open University, Karnataka offers Diploma courses through the distance mode.

All the best!