Difference between Tokui/Jyouzu

Can somebody tell me the difference between Jyouzu and Tokui and when and when not should be used? Also I'm assuming that Heta and Nigate are different in the same way that Jyouzu and Tokui are different?

Those are at times used interchangeably. But "jyouzu" (or "jouzu") is objectively "good at, excels at" something, whereas "tokui" is more subjectively "feel confident/comfortable with" something ("tokui" when used in a verb phrase even means to be proud, excessively to be somewhat boastful).

So if you watch someone, for example, playing tennis and wants to give compliments, then you say:
- Jouzu desu ne.


Also, "heta" is "not good at, bad at," and "nigate" is "don't feel comfortable/confident with (thus not good at it)."

I was taught that "jouzu" cannot be used when referring to the speaker, him or herself. Is that true?

So when being asked "nani ga jouzu desu ka", should the reply be "�` ga jouzu desu" or "�` ga tokui desu"?

tuby,
Well, since "jouzu" is "(objectively) good at (something)," if you said that about yourself, that is like praising yourself, if you know what I mean :)

Wakarimashita. Thanks! ^^