Hi there, I agree with the advice above – people need a reason to come to your site.
Think the famous second hand bookshop in Paris. What makes it special, why are people from all over the world drawn to it.
How can you recreate that experience online.
Another key part opportunity here is to create a community of people that love books and need a venue to find the them, a book club for example.
There is some PWC research that shows how the internet is facilitating communities of shared interest coming together through special interests like books. It might be worth trying to find that research, it’s about 6 or 7 years old now but very relevant to your business.
Lastly I’d encourage you to have a think about what you are trying to achieve – what does success look like and therefore what plan needs to be in place to achieve it. Small digestible steps will get you there.