Focus on things that reward people who come into the shop. They call that experiential marketing these days.

• Have a membership list and send them news about events. - Such as:
• Book authors for talks.
• Book school events where authors work with kids to introduce them to writing as a career
• Make a writing room, or even some paid priority members writing cubicles.
• Be a small publisher. Take in members books and publish them. Have openings for the writing club book launches. It's not hard to publish any more. Amazon is your frenemy!
• Host NaNoWriMo work groups with a progressathon wall chart and a finishing day party.
• Fundraise for special editions like leather bound books.
• Run events like local entertainers reading excerpts. Local sex workers reading erotica is very popular in some places, but actors reading thrillers would work too.
• Have movie nights where you play films based on books and have a discussion group - (and sell the book for next time).
• Make your own Audio book club taking volunteers to create content. Create a podcast or YouTube out of this.

Wow - These are great ideas! I'm opening a bookstore!!!