Stick to a routine. When we put Poppy to bed as a newborn, and she woke up in the night for a feed, I would quietly go downstairs for her bottle and bring it up, take her out of her basket without saying a word, and without turning the light on, feed her, burp her, then put her straight back into the basket (still no light on, still not talking to her). Even if she woke up several times I would stick to this. She quickly learned the difference between night and day and was sleeping through the night at around 4-5 weeks old. xx