In the "coping with twins" section of my brain is quite a bit of practical information and advice I wish I'd been given before I gave birth. Here's my attempt at extracting it from the grey mists and putting it down in writing:
Breastfeeding twins: use a triangular pillow and the "football hold", so that you've basically got a head at each boob and their bodies under your armpits. You'll need someone on hand to pass you each baby at first, but before long you'll be more used to handling them. Of course you can feed each baby separately, but just bear in mind that this means each feed will take twice as long. If you're also trying to express in between feeds as well this means you're pretty much feeding quads!
Bottlefeeding twins: sit on the floor, back to the sofa, with a baby facing you on either side. You can put them in bouncy chairs, car seats or on bean bags - as long as they are propped up a bit. You'll be more comfortable if each seat is about the same height and won't get "arm shudder" halfway through. Make sure you've got everything you need (muslins, infacol) before you start and the TV is on something decent. The number of times I've got myself all set up and then realised I'm stuck watching Police, Camera, Action, or a DVD that has finished so I have to sit watching the credits. I would go for a box set of something gripping, so that you're actually looking forward to the next feed. It's quite likely that this process will be a bit messy at first and you haven't got a spare hand to catch the dribbles. I would put a muslin around the baby's front, and then a bib with a spongy dribble-catcher cushion (Tommy Tippee, I believe) over the top to soak up the excess.
Burping twins: with either method you will probably need to get some wind out of each twin after a feed. I would sit one as upright as possible while you wind the other, and then swap. One of your babies might be able to bring their wind up on their own if they are sat upright, which is awfully handy. With mine it was quite often a race to get baby 1 to burp before baby 2 started screaming or being sick. If one baby finished their bottle before the other I was able to slide my arm under them, lean towards them and get them onto my shoulder, whilst keeping the other bottle in the other baby's mouth. It can be done; just takes practice and you'll get lots of that.
Picking up twins: I don't think there are many times when you really need to pick up both babies at once. Your job is not necessarily to get them to stop crying as quickly as possible, and actually if you leap up to comfort them straight away they will get used to this and expect it every time. Twins need to get used to self-settling and to do that you need to let them cry a bit and not pick them up at every whimper. Personally I used dummies to calm them down and get them settled so that I was able to carry on with all the cleaning, sterilising, expressing, washing, organising and sorting stuff out I had to do. Often I was in the middle of doing something in the kitchen when they started crying and I'd always stop and ask myself whether it was of greater benefit to drop what I was doing and go to them, or carry on because whatever I was doing was invariably for them. Quite often by the time I'd finished what I was doing and went to settle them, they were already asleep again.
In the house with twins: having various places to put babies down is really useful as you move around the house - cots, moses baskets, your bed, the sofa, bean bags, bouncy chairs etc. In the early days, however, don't feel like you've got to take them everywhere with you. Set up base camp (in the sitting room, for example) and keep returning to them when necessary. Spending time elsewhere will really help your sanity! I did have one baby who was very unsettled in the early days, so if I desperately needed to empty the washing machine I put her in one of those cloth baby-carrier thingys and got on with it. The motion usually got her to sleep more or less immediately. Word of warning: don't do the washing up with a baby on your front. They get really wet.
Transporting twins: carrying two carseats isn't ideal, but this is pretty much how I got from front door to car, and from car to wherever I was going in the early months. I reckon I was able to carry both seats until my twins were around 9 months old or so, but please don't feel that you've got to take them everywhere together. This "never leave your child unattended" business doesn't really apply to twins, so it's fine to leave one in the house while you take the other to the car. Just make sure you've got your house keys! A friend of mine had a super trolley-thing that she put the bigger twin's carseat on so that she could wheel him around like a suitcase and carry the other twin. I would recommend getting the car seat bases, which go in your car so that you can just clip the car seats into place and off you go. No fannying around with seatbelts. I also really loved my pushchair with carseat adaptors, so that I could just clip the seats onto the pushchair frame and off I go. No need to disturb the babies, and really easy to do for a shopping trip.
Supermarket and twins: this can be a bit tricky. This is what I do: for a small shop I put the twins in the pushchair and carry a basket over my arm, putting heavier stuff in the bottom of the pushchair (and hopefully remembering to pay for it!!). For a larger shop you need to lock the babies in the car while you go and find a trolley. I don't really see any other way of doing it, unfortunately. I just try to find a trolley as quickly as possible and get back to the car before they are hysterical. If you are having trouble finding a trolley with 2 seats, get a car park attendant to find one for you, tell him where you are parked and get them to deliver the trolley to your car. Be assertive: you're the customer and you've got twins for goodness' sake!
Night times with twins: the big question people always ask me is whether my babies used to wake each other up. And the answer is..... sometimes. And sometimes not. I was always amazed when one was screaming their face off and the other was fast asleep, sometimes just inches away. In the early days I think they are able to tune each other out to a certain extent, so that they can sleep through each other's wailing. If mine both woke up at the same time it was more to do with them being in the same routine than anything. To get them into the same routine, you need to feed them at the same time, night and day. This means when one wakes up for a feed, you have to wake the other one as well. There's really no point feeding one, settling them, getting back into bed for 10 minutes, and then having to do the whole thing all over again with the second twin. My husband and I would decide before bed which baby we would look after during the night and we just got on with it. Really this is the biggest nighttime tip: doing it together. There are two babies, there are two parents - it has to be a team effort.
To deal with looking after twins you need a sensible plan of attack, as well as the ability to change the plan when it's no longer working. Make sure that rather than getting stressed and angry when things go wrong, you take a step back and look for a different way of doing things. Remember: it's all totally possible! I've kept mine alive for nearly 20 months now!