I think just a lttle expanison on Mr./Mrs/Ms. Mcfluff's good advice might help.
First, if you're going to marinate the tofu to add flavor, be sure to select the firm or extra firm variety, not the soft. Secondly, it's ironic that with tofu (which is sort of an unfermented soy based cheese), the colder it is the more readily it will absorb flavors. In fact, the quickest way to marinate tofu is to freeze it and then thaw it first. This has the added advantage of making it tough and more easily handled for dishes. However, the colder the better. Place it in a glass or plastic container with whatever the marinade is and cover with plastic wrap. Again, if it's good and cold or frozen then thawed, it will just take a few minutes.
I use a lot of extra firm tofu sliced into 1/2 inch thick strips about two inches long for my highly successful (at least by my judging) Hot and Sour soup, which is really good for a winter soup For that purpose, I marinate it in a Balsamic vinegar and Chinese Chilie sauce for about two hours before frying lightly in wok oil. This locks in the flavor when you're going to use tofu for soups or sauces.
Best of luck!