Our routine is much the same as AJP & Jodi. I find Charlie is really cranky around 5pm & would go to be then if I let him, but we would be up waaaaay too early. So I feed at 5pm & play with Charlie to keep him amused til DH gets home, then we try hold off as close til 6.30 for a shower or bath, that way he's all relaxed when he has his bottle, burp, into his sleeping bag. Pop him in bed wide awake & walk out...usually we don't hear a peep & he's been sleeping through the past month now. I think it's due to unwrapping him as he's always asleep on his side or tummy. I also have a radio going day & night, he seems to like the noise.
As for curtains, much the same here. At night if he wakes we make little fuss, little as possible light etc. During the day I get him up, open curtains etc.....though I too still close them to make it dark for arvo sleep.