This is the official style guide that appears on the add/edit venue pages of Foursquare’s site. Unfortunately it’s not possible to link directly to it, so we’ve added it here for reference.

• For chains or venues with multiple locations, you no longer need to add a location suffix. So “Starbucks”
  or “Apple Store” is fine (instead of “Starbucks – Queen Anne” or “Apple Store – Uptown”).
• When possible stick with abbreviations: “Ave” instead of “Avenue”, “St” instead “Street”, etc
• Cross Street should be like one of the following:
  • at Main St (for venues on a corner)
  • btw 2nd & 3rd Ave (for venues in the middle of a block)
• Cross Street should not repeat the name of the street in the address.