:) they are good questions!
it is appropriate to offer a draw when you think the game is a draw :) meaning, you don't think either side can make progress to win.
resign? well, when you feel you don't have a chance to win anymore. this is mostly personal preference.
Two questions of chess ettiquette:
1) When is it appropriate to offer a draw?
2) When is it appropriate to resign?
I realize that the first may not actually be an ettiquette question, but I really have no idea how to use these two options. Makes me feel kind of stupid, actually.
-Justin