You do not need to get a shop since you are still in school.
1. Get good suppliers. That is the backbone of this business. You did not specify you location, I would have given you a list of suppliers in your area.
2. Brand yourself: A name, facebook page, even a website. Make a business card with your phone number on it. Also, you can make posters and put them at tailors shops.
3. Sell quality
4. Sell to university staffs. They always have cliques, and every member will probably want to buy from you.
5. Keep proper records
Make your money and send my share.