You are at the very beginning so there's a lot that you will have to learn by trail and error.
As far as social media goes, I don't believe the return is worth the effort for very small businesses. For example, if you are on twitter and all you do is post items for sale you will not get many followers, so you end up posting a bunch of social posts and throw in an occasional promo for an item. This takes a ton of time and yields very little sale.
Social media works great for big companies because 1) They already have a following and 2) they have people whose sole job is to post on social media. For a one man/woman operation time is the most important thing and it's better coming up with new products, refining old ones, and making the descriptions and titles the best they can be.
I have over 3000 tweets on twitter and can point to only 2 sales from them. If each tweet took only 10 seconds, I took over 8 hours of time. Not worth it.