Secret Places (4)
This is in the bachelor's pad with the large television. There are two secret places shown in the snapshot. Blast the bottles (right side of image), and walk through the shelf to find the first secret place. Then, open the framed picture (left side of image) to find the second secret.
Go to the KTIT radio broadcasting station. The room containing the red access card is considered a secret place, even though it's mandatory to have that access card!
You'll find this room in the KTIT station. Walk through the red curtain at the back of the room to find the secret place.
Secret Messages
"Blast the bottles": Found in the room with the large television and the rack of bottles. It's hidden in a dark corner beside the cracked wall (nightvision goggles required). It is, as you might have already suspected, referring to the rack of bottles as described in the secret place listing above.