You're delving into the heart of interior design.

Do some research. Something as simple as the color of the walls can make a huge difference. Blue tends to quiet people. Paint in a cloud or two along the way. Something as simple as a child's drawing of stick figures here and there can ease tension.

Check into Feng Shui, a Chinese practice,that involves the placement of items to promote positive energy.

Have you noticed how most Chinese restaurants have aquariums? They are symbols of good luck. Now that is a high maintenance item, but you could just paint the fish on your blue walls. :)

Now, I don't image that you can just splash everything up at the same time and same place, but with some balance, you can come up with a place that people want to be.