yeah that can be very difficult. I think you should aim to _season_ the tofu (i.e. salt -- or slight umami with soy sauce), but your primary flavour should still come from a sauce that's on it. I really like sticky sauces that cling to tofu like buffalo sauce or sugary, sticky glazes.
It's not a problem for saucy dishes like a curry, but even experimenting with friends and borderline "molecular cuisine" techniques I have never once managed to flavour tofu itself :(