What's the best way to handle a situation where you have, or expect to have multiple offers?
The ideal situation is that your several offers come in about the same time, and you make a choice. this is not how it happens though. You may have an offer, and several near-final interviews lined up for the following days or weeks.
One way to handle it would be to ask for a longer time to decide on the first offers you receive. 2 weeks? This gives time to rush the rest of the things you have going through to an end. i question whether asking for 2 weeks to decide is reasonable though. My guess is that an employer would see through that and force your hand.
Another way to handle it would be to accept the first offer, and ask for a reasonable period before your start date, then simply "quit" the first position before you ever start if something better comes along. On one hand, employment is at-will, and employers exercise this fact regularly. On the other hand, it seems morally the wrong thing, and has the potential to burn some bridges.
And of course the last option is to simply evaluate each offer in isolation, and accept or reject within the given time frame.