If the lights (with plastic ceiling disks) and pictures in your Lundby dollhouse keep falling down, you're not alone! Instead of using glue or a permanent adhesive like double-sided foam tape, you may want to try a removable adhesive like Glue Dots. They come in a roll and can be found at most craft stores.
I simply unroll the backing paper and touch the back of the item I want to hang (in this case a Lundby clock) to one of the sticky dots.
The dot is transferred to the back of the clock, which is now ready to hang.
Removable Glue Dots are nice because they won't stain paint or paper, and you can just peel items off and redecorate as you please. But for heavier items they're sometimes not quite strong enough--especially in humid weather.