Many people have a hard time with tofu, but don't give up! It took me a LOT of trial-and-error before I finally got it right.
Some simple guidelines:
1. All tofu needs to be drained. I usually place a weight on it and let it drain for at least an hour. Sometimes two. Some people drain it for only 20 minutes, but it's up to you.
2. Tofu tastes best when it's marinated. I marinate tofu almost everytime I use it, for at least two hours. However, it needs to be precooked first! The cooking process helps the tofu soak up more of the yummy marinade. I usually dice the tofu (after it's been drained, of course), then cook it over medium-low until it's nicely browned and really dry.
3. If you freeze tofu (which is a really great idea because it becomes denser and more hearty), you need to thaw it before you use it. I don't usually marinate the tofu when it's been frozen. I just squeeze out all the extra water and crumble it up into the pot. Keep in mind though, that you can't freeze soft or silken tofu (it has too much water in it). Also, frozen tofu stays good in the freezer for up to three months.
Now try it for yourself!
This website has some helpful advice and even has some directions on how to substitute tofu for such things as cream cheese, sour cream, and ricotta/cottage cheese.