While working through the process of conversion, the budding erstwhile proselyte is expected to do all the mitzvos. Sort of a dry run, if you will, to really ensure his sincerity. He also has to learn, of course, both to know what he is getting into (yeah, right...) and so he will actually know what he needs to do as a Jew. At some point I learned about the mitzvah of t'vilas keilim. I was all set to fulfill that mitzvah when it dawned on me that I couldn't. Since the mitvah is to tovel keilim that used to belong to a goy and now belong to a Jew, this mitzvah was just going to have to wait. (My wife didn't have the mitzvah either since they were my keilim. We realized later that I had been feeding my family treif m'd'rabanan because of bishul Abba-the-goy; but that's another story.) Avraham Avinu (and all the avos) fulfilled all of the mitzvos: matzah, korban pesach, shabbos (some interesting details there); and even mitzvos d'rabanan, such as...
This is a paraphrase of the pasuk in t'hillim 84:7 -- "mei'chayil el chayil" -- which means "from strength to strength". In this case, it is my thoughts and ideas to those who are strong enough to be interested :)