I have a book on preludes and fugues. Whilst i can hit the right notes and i follow the fingering my playing is flat and dull, i cannot obtain brightness or lightness, or the beauty that i wish to hear. Also half way through playing a prelude/fugue my fingers become tired and the notes cease to be correctly tempered.
First of all you need to learn not to get frustrated if you hear the greats playing this music, not being able to play it like that yourself. As an amateur, which I assume you are, you can never compete with the professional pianists, and you need to get to grips with what you can
do. Be happy with the things that do
go well, instead of unhappy with the things that don't. If necessary, scale down your goals as Eddy suggested. There is so much beautiful music which is less demanding than the WTC.
Stay critical about your playing, but do not underestimate it either. If you can play the WTC and hit all the right notes, that is already far more than 99.9 % of people can do !
And by all means, do get a good teacher if you are serious about playing. Even if it's only for a couple of sessions a year.
I hope this helps some.