We actually used reverse psychology when we moved into our current home. The largest bedroom other than the master is downstairs in the basement and we both felt like our oldest child (a girl-14) should have it. Her younger sister (who was 12 at the time) was a little stinker and had stormed and pouted about us moving at all, so we knew that she would want the "best" room. The bedroom on the main floor is also large and connected to a bathroom so it was just as good a deal or better than the larger room but we KNOW this child. So I told my oldest daughter to ask for the main floor room and make a big deal out of thinking that the oldest one should get first pick. She agreed and did a perfect act. My younger daughter bought it hook, line and sinker and demanded the main floor room. We all "finally" agreed and my older daughter moved happily into the larger basement room...which she had wanted in the first place. After about a week, my younger daughter noticed that her sisters room was BIGGER than hers, but it was too late by then!
When we had our last boy, making three of them, my older daughter volunteered that large bedroom for the three boys to share and moved into the SMALLEST room in the house on her own. To thank her for being such a good sport and a generous sister, she got a new bedroom set as a thank you and was perfectly happy.