Earplugs are a good shout, but personally I always struggle with eye masks. I love the idea, but there's something about having the pressure of something around my face that stops me getting to sleep. If I'm compus enough to either remember to buy one or make my own, I find that sitting in the tent porch with a peppermint tea and a smoke to decompress for 15 minutes before bed is perfect.  Especially if I'm up high like Big Ground and look at the site while coming down, it's a lovely way to