These are the locations from what I could tell:

Salon Front- The Tree with the heart on it and Harry's Hideaway (next to the front door)
Salon Lobby & Parlor- The Candles, the computer, the painting, the massage bed, and the basket of towels.
Apartment (Inside)- The Fridge and the Magazine on the coffee table
Apartment (Outside)- The graffiti, the classic car (lower left), and the garbage can under the stairs
The Mall- The Ad for your massage parlor, The Berry Mix ad, and the Cheers Sign.
The Car Dealership- The Yellow Car, The sign above NPC, and the White SUV poster.
The Green Store- The Ad in there.

That should be everything I can think of. Happy hunting.