DD2 had significant health issues so TBH "routine" was never something that happened for us. I also had a 12 month old who was a very bad sleeper/settler at the time too.

The first few months weren't fun, but the turning point for me was when I just sort of gave in to it all - threw the idea of routines and schedules out the window, gave up trying to settle DD2 down for a sleep etc. DD1 still had her sleep (such as it was) when she was used to having it and DD2 usually fell asleep while bfeeding on me at the same time I was settling DD1 in bed. Our days got a lot easier. With the issues we had with DD2, DH had to really step in with DD1 and do a heap of stuff with her so I could concentrate on DD2. I had a few times where I would just thrust DD2 at him and leave him with a screaming baby so I could spend some time with DD1. DD2 also spent a considerable amount of time in a sling or ergo so I could do things with DD1.

I'm hoping this time around with significantly older siblings life will be a whole lot easier, but its really so reliant on the character of the little person who comes into your life. A happy, easy going baby and you're laughing. I really want to know who I have to pay to get me one of them ;-)