I see a lot of people getting more than 2 offers at the same time.

1. How do you manage to get all the offers or get the interviews scheduled very close? Each company contacts at a different time
2. Do you get a long time to "accept" or "decline" the offer?
3. Do you rely on verbal offers or demand for mail copies?
4. What if you accept the offer and then get a better one? Have you gone back, declining it?