What sort of curtains do you have? We have blockout curtains and it works a treat, I would trip over stuff if I went in there when the curtains are closed. Another thing to do is (this is going to sound extreme) but make sure the curtains are tucked in so no light can be seen through any cracks LOL! I made sure Paris' curtains where slightly wider so I could do this.

Spotlight has some cheap blockout curtains that are really really good!

*hugs*
Cailin