Kissing etiquette with relatives other than your spouse is very simple:

1.  Kiss on the cheek, not on the lips.
2.  A cheek must be offered before it is kissed.
3.  Only a woman may offer her cheek to be kissed.
4.  A man must not offer his cheek to be kissed.
5.  If a woman does not make it clear that they are offering their cheek to be kissed, you must assume that the woman is not offering her cheek to be kissed  and you must not kiss her.