What is the best way to send paid traffic to general ecommerce store?

In niche stores, it is the process of making a fb page/group then post your offers in your page or make a facebook ad using one of your products then send it to your targeted traffic. Am I right? It is easier in a way because everyone has the same interests.

So how would you do it for general stores since you are promoting different niches? how would you target your traffic? How can you grow your fb page/group if you have fans/members with different interests. How can you engage with ALL of…

What is the best way to send paid traffic to general ecommerce store?