Arrive early, 5 mins at most.
In a coffee interview, just like any type of interview, break the ice. Appreciate their time by asking how long they have right at the beginning. Make sure you respect that amount of time. The coffee interview is also an opportunity where you can, more often than other types of interviews, get information from them about their employer or about the appropriateness of your objectives. Due to its casual nature, make it a two-way conversation.
You can bring your resume with you in an envelope or folder, however, keep in mind that you are in a public space and there is a good possibility that people you know may be around, and resumes are indefinable pieces of paper. You can walk through your resume, but remember; you’ve got maybe half an hour and can’t get through the entire history of your working career. You need to be succinct and get to the point.
In a coffee interview you have only have time for brief conversation. It’s informal, but opportunity to provide a concise summary of who you are and what you have to offer. You have about five minutes to do that (remember, you’ve already spent 5 minutes getting coffee) so that you can spend the next 20 minutes getting your coffee mate to talk about opportunities while also asking questions so that you can follow-up.
At the end of the coffee interview, make sure you leave with an opportunity to "follow-up". Request something of the person you’re sitting down with; either a contact name or a request for an introduction - something that you can actually follow-up on. A coffee interview takes up half an hour someone’s time and failing to follow-up might suggest that you do not respect the value of their time. Following up is a great way of turning one coffee into many more coffees.