Help in finding studs and replacing electrical outlets.

[chemara]

Hey all,
I'm new to the forum, and I'm finding lots of great info.
Hubby and I own a 1984 Liberty home, 16x 80, Vaulted ceiling in the Living room and kitchen.
My questions are: How do I find studs in the interior walls, There don't seem to be any. and I need to replace some electrical outlets that are installed using remodeling clips. Is it possible to install ceramic tile or glass tiles for a back splash? I've heard it's not a good idea because of the constant settling of the home due to lack of permanent foundation.
I would like to hang a mirror weighing about 40-50 lbs in the living room.
We have done some updating with a new bathroom in the master bedroom, and remodeled the kitchen. Our contractor installed new dry wall, and new sub-floors for the sheet vinyl floor. Any info is appreciated.

Thanks,
Chemara