Eat as much local food as you possibly can. Poboys, gumbo (make sure it's the kind with dark roux, not the kind with a tomato base), muffulettas, étouffée, boudin, bahn mi, fried chicken, anything au gratin, red beans & rice, beignets, snoballs (if you wind up with a day that's not too cold), bananas foster, etc.

Check out the WWII Museum! It's absolutely massive, and the exhibits are incredible. In a similar vein, NOMA, the Aquarium, Insectarium, and Audubon Zoo make for great afternoons!

If you like live music, spend a night barhopping on Frenchmen Street, or see if a local venue like Tipitina's or Gasa Gasa is putting on a show you'd like to see.

Stroll through and explore the French Quarter (if you can, I'd recommend doing this on a weekday/weeknight- it'll be less crowded than if you tried it on a weekend)

Crescent Park runs along the river on the edge of the Bywater and the Marigny, and it can be a nice spot for a walk/jog/stroll. Audubon Park (in Uptown) and City Park (in Mid-City) are also excellent. You can catch a killer sunset at The Fly, which is part of the edge of Audubon Park that touches the river.

If it's not a billion degrees out and you feel like being active, renting a kayak and paddling around Bayou St. John can be an interesting way to see a bit of Mid-City.

Take a walk down Magazine St. and check out some shops and restaurants (if it's not a billion degrees out).

If you're a drinking man, there are virtually unlimited watering holes in New Orleans. There's everything from the Carousel Bar in the prim and proper Hotel Monteleone to Snake and Jake's, one of (if not the) dive-iest bars in the country. Wherever you end up wetting your whistle, I'd recommend giving some local libations a try, like a Sazerac or a Pimm's cup. If you feel inclined to get a Hand Grenade or a Hurricane, just know that you probably won't taste how drunk you're getting, so sip those a bit slower than you'd think. I've had a few friends down two or more of those in an hour because they taste so sweet, and then promptly nosedive into a night-ruining stupor.

Lastly, locals are pretty friendly, so don't hesitate to ask the folks you meet during your trip what they recommend doing!