Of course, you should do more than just advertise and wait what happens next. Take the initiative and stay active. Keep updating your Facebook page and stay in contact with your fans and followers. Here you can find a few useful and free tips for what you can do during your campaign:

• Respond to every comment on your posts and address the users personally
• Encourage the FB users to purchase your product in a direct but polite manner
• Contact the customers that really like your product and ask them to share your campaign posts
• Create posts that say “Link someone who really needs this shirt” in order to broaden your reach
• Create interactive quizzes or raffles so that people comment your post
• Encourage your customers to post a photo of themselves wearing your shirt
• Post subject-related content e.g. videos or other interesting media

These are just a few ideas and guidelines. Be creative and pull out all the stops in order to promote your campaign. Don’t concentrate on just one type of advertisement. Use the free ads but also the ones that cost money, so that you receive the best result.