There is no magic way to gain followers on social media (I wish there was!), but there are a lot of things you can do to help build your following...
1. Post quality content - Quality content will help bring in quality followers.
2. Offer follower rewards - Have special offers available only to your followers. This will help encourage people to follow you on social media to gain access to those special offers. (Coupons, Giveaways, Pre-Sale, etc.)
3. Cross promote: If you are on multiple social media platforms make sure to tell your followers where else they can find you on social media, and make sure you are offering different content on each platform! If 1 follower follows you on Facebook, Twitter, Instagram, and Pinterest... and all you do is post the same thing on each platform they might begin to feel a bit spammed (spam = risk of unfollowing)
4. Research and use hashtags appropriately: Hashtags (when used appropriately) can help get your SM posts in front of potential followers that have an interest in what you are posting about.
5. Fill out all of your account information! - This is something that does not get mentioned enough for social media.... Different social media sites offer different sections to fill out extra information about yourself and/or your shop. Make sure you fill out all of these sections! When potential new followers land on your page they will want to find out more about you and/or your shop before they click the follow/ like button. If you don't have that info available to them then they might just move on.
6. Follow and Engage With Others: You need to be social on social media in order for anyone to want to follow and interact with you and your brand.
I have a lot more that I can add later, but I need to run and pick up my daughter from school :P
But remember this...100 engaged and active followers is far better than 1000 who never engage or interact with your brand on social media!
Quality is far more important than quantity... Try not to focus on the total number of followers... Focus more on the interaction you receive from the followers you already have!
If anyone else has suggestions, or other questions feel free to jump in to the conversation!