I think you are thinking of domo rather than dozo. You could use domo but I personally would stick with arigatou. Domo just sounds a bit curt to me, especially coming from a woman.. dozo is sort of like please but not in the sense of asking someone to do something but rather inviting them to do something. Such as please sit down, please go first, etc. So if you say dozo to a waitress bringing over your food she may think you are inviting her to sit down with you! ← If she's cute, I will invite her to dine with me....Definitely, keep "dozo" in mind.