You’re not a mind reader—but that’s no excuse. Finding the engagement ring she’s always dreamed of, without asking her, is a puzzle most men will have to solve sometime in their life. But have no fear, there are plenty of ways to work out what she wants without spoiling the surprise. Listed below are a few hints and tips to help you unlock the mystery to the perfect engagement ring.

FRIENDS

Every woman, at one time or another has talked about her ideal diamond engagement ring with her friends. The best way to determine the shape and style your fiancé wants is to simply ask those who know.

RING SIZE

There are plenty of other ways to verify her ring size (besides taking a tape measure to her finger while she’s sleeping). A good way to determine the circumference of her engagement ring finger is to find a ring she wears often, borrow it for a day, take it to a jeweler, and have him determine its size. If she doesn’t wear rings, playfully ask to compare hand size. Place you hands together and use your best mental estimate of how much smaller her finger is than yours. This will give you a rough starting point.

ASKING WITHOUT ASKING

In those rare cases where a woman has never divulged her ideal ring information to anyone, a good way to extract this critical information is to try to get her to talk about it. Take a walk by a jewelry store and stop in front of the window. Point to a ring and point out a ring you like. Stay for a few minutes, pointing at rings, and carefully gauge her reaction to each one. This will give you a better sense of where her aesthetics lie, and can also serve as a good starting point for your diamond shopping.