An accurate birth time. You need to know your birth time down to the minute. Down to the hour will do in a pinch. However, if no one remembers, you can rectify a birth chart, but it will take a long time. As a few people if no one remembers what time of day you were born. A birth certificate or even a baby book should have a good time in it. 

The actual town you were born in. This should be obvious, but there are people who don’t realize that even a few miles can make a difference. If you were born in Skokie, say Skokie, not Chicago. If you were born in a tiny village you can’t find on the map, give your astrologer a decent idea of where it is so she can find the latitude and longitude of the place.

A good attitude. No one wants to work with a sourpuss or hater in any field. Even psychologists would rather work with someone shy and meek than combative and brash. If you want to fight, go to a boxing. An astrologer wants to work with you, because a reading is a collaboration, not a competition.