I don't think this has ever been posted so in case anyone was wondering, here are the basics of the Hotel Dusk true ending:
1. Beat the game. Hooray, you're very accomplished . A star to make you feel important!
2. Keep your nose clean. Get as little game overs as possible (although you can still get away with a certain amount I think. Just don't click Try Again if you get one.)
3. In chapter 8 or so, Louie will say he picked up an extra tape out of Dunning's ass pocket that fell out. Translate it once you get do the part where you fix the tape in Louie's room.

7. Profit!