Don't use your bed excessively for activities you would/ should/ could do elsewhere- watching tv, laptop use, work, it will arguably keep brain activity high thus decreasing its ability to shit off for sleep. It can also give your sleep life negative connotations, going to bed is not something you look forward. Additionally, recently I read that if you wake up in the night and can't get back to sleep- get up and do read in another room, until you feel tired and then return to bed- again it is supposed to remove any potential negative associations with your bed/ sleeping.