Most photographers rely on social media to promote their talents to the world. While I do think this is a great idea to draw attention to yourself, if you are looking to sell your photographs professionally you need to think about presenting properly to your different audiences.
When you post pictures on social media, don’t let that audience tell you what photos are good and what isn’t professionally speaking. Your social media audience is rarely a buyer. These people tend to get blown away by overly Photoshopped images. Social media popularity is not an indication of quality. Often from a professional buyers standpoint these photos are tacky.
If you want the opinion of others in your attempt to improve the sale ability of your work you are better off to submit your photos to stock photo sites. Stock photo sites are often community based and a photographer can learn a lot in the forums there. They usually support teaching each other, and all the companies have some aspect of their website that is about educating photographers.
You don’t need to stop posting your photos on social media, you will just want to learn to cater to different audiences. What works for social media will not work for a professional buyer. Keep the audience in mind when you are producing the image.