Two pieces of advice I'd give. If you can, try to avoid sitting at a table where you're at opposite ends facing each other. Try and sit side by side if possible, or, even better, in one of those quiet booths in the corner of the bar. This is more romantic and allows you two to get closer if there's good chemistry.
Also, pay with cash! I know it's rare, but the last thing you want is your card being declined or something, leaving her to pay the drinks bill.