How does one make friends in Washington DC?

Get a dog.

Expensive drinks in expensive areas of town that require you, from Arlington, to take the Metro and then walk 18 blocks because the Metro doesn't go to that specific expensive area of town.

OR go out to the Mexican parts of town and stand outside and smoke. At least 30 Mexican men will start talking to you.

At least those were my experiences when Robofrance29 was in Nova.

That only works on the internet.