I am Christian and I work at an Orthodox Jewish organization. One time I wrote God bless you in a card. I didn't know at that time that Orthodox don't write God but instead they write G-d. My question is what else should I know other than the obvious? I don't want to make a fool of myself or disrespect them or their religion in anyway. Are there other things I should be aware about? Things that I shouldn't do? Like write G-d?