The 90/10 Rule governs social media behaviors. To engage your audience and avoid spamming them, plan out your posts where 90% of your posts give education, enlightenment or education. Only 10% of your posts should mention items for sale.
Another way to put it is out of ten posts, 9 should be engaging and only 1 should be telling people about items to sell. What should you post? Well, that depends on your personality. It also depends on your target market. Remember, you are building a tribe of people who enjoy similar things. What do they like to talk about? Think of ways to draw them into a conversation.