Dogs like to sleep in a place that's warm and secure. First be sure your dog's bed is in a clean area away from drafts. Place an article of clothing or a towel that has your scent on the bed. Or you can use an article that has your dog's smell so he can understand that the bed is his. Another trick is to put a treat or a favorite toy on the bed. If he still refuses to go on the bed, lift him gently and place him there. (This may be difficult if he's a Great Dane). When your dog gets in the bed even for only a moment, praise him lavishly. He'll get the message/