At first when you hear that you may be intimidated fearing you might bore or overwhelm your followers but I'm here to tell you there are ways to promote daily without exhausting your audience.
When choosing your main platform it should be the one where you have the most influence. Usually, this means the one where you have the most followers but this not always the case. You want to choose a platform where you feel confident converting your audience. On your primary platform, you should be creative on how you promote. If your primary platform is Instagram then you can post just about daily on your story as long as you have other content but you might only want to post a 'Call to Action' post on your feed 2-3 times a week. A call to action post is very specific and directs your followers to do a certain action. This does not mean you can't post pics with items from the store and mention it in the caption.
The key to posting daily is posting across different platforms. You have to utilize Instagram, Snapchat, Twitter etc. These are all platforms where you hold influence and can generate sales. But every platform is different so make sure you adjust content accordingly.
Posting often is important but when you post can play just as big of a role. Gauging when your audience is most active can greatly improve the rate in which you convert your audience posting these times.
I've mentioned a couple times including a call to action and that is because it makes all the difference. When you ask you receive if you tell your audience to click the link they will. But if you tell them to click the link and use your promo code on a specific item they will too. ;)