My husband and I had planned on having three kids. At the ultrasound midway through my third pregnancy we got the unexpected news that we were having twins. At the end of that very long day I phoned a friend with twins. "Oh your life is going to change." She said. "But you are going to have so much fun." Whether the news that you are going to have twins is shocking and unexpected or everything you've ever wanted, parenting twins is a little different than parenting a singleton.
There are some things that aren't that different: potty training, learning to dress yourself, shoe tying, etc., are pretty much the same from child to child. The method that works for one child might not work as well for another but the basic concepts are the same for everybody. For twins, you just get to do it twice. Some choose to double up. Others do one at a time; the method will vary with your personality and that of your children.
There are other things that are very different.
Strangers feel free to critique you. You will hear all sorts of strange comments from people you know and many you don't. Some will be obnoxious, some will be kind, some will be painful, some will be ridiculous, and some won't leave you alone and follow you through the store to make their point. You'll need to develop a tough skin and maybe even have some preplanned comebacks for those who are extra inquisitive.
At first parenting twins is REALLY REALLY HARD. It gets easier, and better, and more fun, and is really really worth it. With more than one newborn in the house everyone will have less sleep, and less time to eat, shower, or even think. These first few months are exceptionally difficult. Do whatever you can to keep your sanity. Accept offers of help. Remember, no matter how awful it gets, after a few months, the babies will sleep more at night and you'll find a routine of feeding, rocking, sleeping, and bathing that works for your family. You'll again notice that the sun rises in the east. Those few months of terror will start to be forgotten in the adventure that lies ahead.
Never underestimate what two minds put together can accomplish. Two can outsmart any child-proofing measure doubly fast. At a very young age my twins could climb out of and into each other's cribs, unlock any childproof doors, climb high enough to reach items placed far out of reach, and many other feats of naughtiness that my singleton children could only dream of.
Once you have survived the terrible two's and threes, life throws new curveballs at you. You have to decide when and where to separate your twins. Do you want them in different classes at church? At school? To have individual parties and events and friends? Do you want them together as much as possible to take care of each other? There is no universal rule that fits everyone. Are your twins boys, girls, or boy/girl? Do they work well together, rely on each other, or do they want their own friends, parties, etc.?
Each new stage has its own learning curve. You need to be willing to ask for help, talk to your family, and make decisions about what is best together. Parenting twins is a blessing. One of the hardest blessings I've ever had, but when two sit on your lap and say "I love you mom." It is oh so very worth it.