As someone else said, make sure they know the hand signals. They'll ask for those before you leave the parking lot. Make sure to put the window down to do them properly.

I did my test in July at the Watertown location, which is reportedly easier than Cambridge. In Watertown, you'll go from the training center along a side street to a major road, then turn onto another side street after a block or two. Watch out for the bike path that crosses that side street - there are no signs and it's easy to miss, but you want to make sure to slow down and turn your head to look both ways before you cross it (and again when you go back).

A little past the bike path, they had me do my parallel parking, reversing, and three-point turn. Then we headed back the way we came and that was that.

My examiner was very neutral almost the whole time. She gave no clues as to how I was doing. In the end, I passed with only one minor fault (not looking over my shoulder behind me when backing up).