Hi darl, I may be going against the grain here but I started DD on a routin at 2 weeks, I was admitted to the MBU so they have mothercraft nurses and I really thought '2 week old into a routine, hahaha' but within a week she was falling into it.
Basically got her up same time everyday, fed at same time (eg every 3 hrs during the day and then on demand overnite) and didn't let her sleep longer than 3 hr stretch during the day (and day sleeps in a bright room with a bit of noise) to get her used to what is day and night. It took a week of being all over the place but she fell into it and really thrived on routine....
And now is 5 months, feeds 4 hourly during the day, and sleeps a 10 hr stretch overnite (7pm to 5am with dreamfeed at 9pm) and decent 1-2 hr day sleeps. HTH