If you want to earn money by online store,you should lower your inventory risks and capital take up.And more important thing is that you have to increase goods category with wholesale price.
This is how i do. Create one good fanpage, post some good image and video. Use some money to advertise your fanpage. Keep engaging. Once your fanpage have 1000 like. create another fanpage and use your first fanpage to grow 2nd, 3rd, 4th fanpage of your own. Keep engaging. Once you have lot of engagement, start monetizing. Affiliate, your own product, dropship, or even sell advertisement. keep doing it and moving forward.
knowledge is the king, if you know something that not everything else knows, put it into practice, online is just like offline marketing, you need to find your niche , or find out what you are good at and put it into practice online...