Bring your marriage certificate, her birth certificate, and anything else you have that will show you are a couple ie banking, utilities, house title or lease agreement etc etc. Allow yourself way more time at the airport than you think you'll need.
It's been 9 years since my wife's first trip out of the country but it seems that not much has changed. Just last July my wife was asked for her passport AFTER the immigration counter while we were in the security line. In our experience the female agents have been the most ... thorough.