¿Cuál es tu estación favorita?
¿Cuál es su / tu / vuestro restaurante favorito? ¿Qué lugar le / les / te / os gusta más?
Specifically for a family relationship, you can ask "¿Cuál es tu parentesco conmigo?".
Ask them.
One way to tell might be if they wear clothes of certain colors most of the time or just simply ask them.
Ask them for it.
Robert Pattinson has not publicly disclosed his favorite season.
Ask them, or search for them on Yahoo.
Ask them.
their birth certificate / ask them / ask their friends / ask their family
Ask first!
You could ask Leona Lewis how is she inspired? who she is inspired by? Who her friends are? What she like is someones personality? Does she have a partner? You could ask Leona Lewis how is she inspired? who she is inspired by? Who her friends are? What she like is someones personality? Does she have a partner?
Quel-age tu?