Parents tend to cloth their twins the same way, and my first tips to parent would be, don't give them identical clothes, and a identical look. And with never, I mean never! It's usually harder to raise twins or multiples of the same gender, because they look more the same way. You should always remember, they are 2 different persons, even they look the same way. Especially with identical twins. There was a pair of identical twins in my class, and it was so annoying, never being able to know who's who. They was wearing the same clothes, they had the same hair style, they behaved the same way. As I said, annoying. As for un identical twins, or multiples, I don't really have any suggestions, because they in most cases will dress and behave different than their brothers and sisters.
I suggest the parents to join a local organization, or a group, with other MOTs (Mother of Twins). There are usually a lot of opportunities for socializing, like exercising, playgroups and family activities. You should make friends that also are pregnant with twins or multiples, or people that already have twins, or multiples. But after a few years, when your children's are older, they should be able to do what they want for themselves. Maybe you want your children to go in the same class. I think this is a good idea, as they make similar friends. But this is not necessary, as I said earlier, they are two different persons. Already from the very beginning, your twins or multiples should be together, so they get well known.
This is my tips about raising twins and multiples, I hope it helps!