I’m not saying that this is the ultimate routine, but this is what I did in the first 7 months:
Weeks 1-7: feed every 3 hours during the day and whatever they need during the night. Feed both twins together (if bottle feeding sit them in bouncy chairs or car seats, sit between them on the floor with your back against the sofa and something decent on the TV). Don’t worry too much about the amount they sleep; just make sure to put them upstairs at around 7pm so that you at least get a couple of hours to yourself without staring at them.
Weeks 7-15: This is when I started getting up at the same time every morning, regardless of what had happened during the night. For me this was the key to establishing the routine.
06:45 - change both babies nappies and start their feed.
Some point in the next 2 hours - babies go back to sleep, put them in their cots, bouncy chairs or somewhere safe and take yourself off for a shower. When they wake up get them dressed for the day.
When they are asleep and it is around lunchtime have something to eat (in another room if you find it more restful) and make sure you drink lots of water.
18:00 Bath time – if you are on your own bath them one at a time, making sure the one you are not with has a toy or a dummy to keep them occupied. They will be tired and may scream or fall asleep. Just plough on – it’s bed time soon.
18:30ish once they are both bathed give them their last feed of the day.
19:00 put them to bed in a dark room. Don’t wait for them to fall asleep, leave immediately. If they are crying leave it a few minutes then go in and settle them. Try not to make eye contact or talk to them.
22:30 wake them up for a feed. Only change their nappies if really necessary, although this might help if they are really sleepy and tricky to feed. Consider getting a TV upstairs so that you can settle down to watch something gripping.
The babies will probably wake between 02:00 and 03:00. Feed them in the dark and get them back in their cots as quickly as possible. Only change their nappies if really necessary.
Weeks 15-20: drop the night feed. Only if they are putting on weight properly and are not really interested in their first feed of the morning.
Once they are sleeping well you can decide to drop the 22:30 feed. We dropped it once the babies were established on solids at around 6 and a half months, but I know of super babies who didn't need it from about 10 weeks.
Once you start solids, the 06:45 feed (milk and solids) is breakfast, the 10:45 feed (solids and milk. Drop the milk when they don't want it anymore) gets pushed later and eventually becomes lunch. You introduce a solid feed at 5pm, which is dinner. End the day with a bottle after the bath at 18:30, bed is still at 19:00. They will have 2 sleeps (09:00-10:00 and 12:30-14:30). This is still my routine at 1 year.