So after a terrible night with my 3 week old son I have decided its time to try start a routine. I foolishly allowed him to have two 4 hour sleeps in the evening, then he was up ever hour crying for food from 11pm until 7am 
Feeling hopeful so far about this routine business as he's been awake for 4 hours straight today and I've been limiting his naps to 2 hours at a time. Then I'll be waking him for a bath and bottle before bed tonight, it's looking promising so far 
When did you start a routine, how long did it take to work and do you have any tips? 
So far I've heard of limiting naps, getting some sunshine in the afternoon (carefully!) and bath before bed every night.