Right away with out a reasonable investment, other than using low v lights you have none.

Amazon.com has become a leader in book sales and so has Barnes and Noble. It's easy to be squeezed out if you're a small bookstore....but it's doable...
For one thing, I agree with the answer before mine that the internet has changed many industries, not just the book industry. So with the acknowledgement that "the game has changed", let's go over what these big companies "are doing right":
1) amazon is awesome because it's interactive. there's reviews, there's comments, there's lower prices you can choose from if you're okay with some wear and tear, etc. Basically, amazon.com is more like Social Networking Shopping Site. It's a shopping place where you can interact with people like you do with Facebook or Yelp.
Many bookstore owners will need to "think outside the box" here to rival the social community amazon.com has built up. Some relatively affordable things you can do is to start a mobile marketing campaign.
You can have a poster in your shop that says, "text us your name and number and we'll notify you of upcoming discounts and sales!" - They opt in, and *boom*, you've got a list of customers to build rapport with and market to over time.
You can also encourage a book group to take place in your store every month, as a way to get your customers involved and talking about your business.
The possibilities are endless, just think of creative ways to draw people in, and for ways to make 'em stay or keep coming back.
The book club can buy the book all at once every month, review it, post the reviews on your store so other customers can see it. Then do it all over again the next month. This way, with the book group, you get sales every month, solicit reviews and interact with your customers, building a loyal fan base.
2) many if not all barnes and nobles have built-in cafes for coffee and little yummy snackies (basically to keep the customers there longer and longer). This is not that cheap, but if you have the budget, consider adding a little breakfast or brunch nook for people to sit, have coffee/tea and skim the book they just bought. The goal is to make 'em stay as long as possible so they keep shoppin'
for more marketing tips and free internet marketing info, go to www.getsmemoreclients.
Hope you like my advice!
=)
Links: www.getsmemoreclients.