Dan's Cafe

Penn Quarter Sports Tavern on Indiana Ave by 7th. Walkable from the Mall, close to the National Archives and Navy Memorial. Great food, drinks, and service.

Edit: why was this downvoted? That place is awesome for a casual meal.

Flash

You can avoid tourist traps by not eating at the food trucks on the National Mall, or at any restaurant near the zoo that has a panda on its signage. And maybe avoid Founding Farmers? The food is fine, just kind of overpriced, and it's where everybody brings their out-of-town families when they come to visit

Other than that, there isn't much of a difference between something for tourists vs. something DC residents do. Search this sub's archives for your favorite kinds of food, or food that's going to be in the general part of the city you'll be visiting.

I guess if this is an opportunity for me to shill my favorite spots, Roaming Rooster is my ride-or-die chicken sandwich. If you're going to the White House, Immigrant Food is nice (though thr service can be slow.) Also, stop by the Pie Shop if you're on H Street; sometimes they host bands on the second floor. Nothing better than a big slice of savory pie followed by live music and drinks.

Founding Farmers /s

The food trucks are so good. You should do that.

"Dan's Cafe" as a running gag on this website is tired and boring. In this thread though, it may actually be the best answer.