Make sure you arrive early as has been advised. I just went at 11:00am and there was a huge line. My number was 358 and the display showed 156, with a large crowd waiting.
JD, I'm sure you mean well as you have given great advise here, but steaming off a visa sticker to make room in your passport is misrepresenting yourself and considered fraud, as you surely know. Getting caught would be some serious consequences, if or when the person is caught. Just because it has been suggested in other visa groups does not make it a recommended course of action, as I'm sure you would agree.
If you have a USA Passport where the last pages are marked "Endorsements", then you have no choice but to apply for a new passport. Immigration will only stamp on pages marked "Visas"...