Instagram is the new word-of-mouth. Food and coffee are inherently visual media. If your latte art isn't Instagrammable, you are missing out on free advertising.
User Generated Content (UGC)
Create a "photo spot" in your shop with great lighting and a unique background (a neon sign, a mural). Encourage customers to tag you. Repost their stories. It builds community and social proof better than any paid ad.
Behind the Scenes
Don't just post the finished product. Show the roasting process, the dialing in of the espresso, the unpacking of fresh pastries. People love to see the craft behind the cup. It establishes authority.