Replying to So i have an interview tomorrow...its kind of an important one

and i need help in answering typical interview questions. Here's one that just always gets me, and im never really sure what the best answer is...because you kind of have to word it so that your biggest weakness is also a strength.

so, if you were in an interview and someone asked:

"what would you say your biggest weakness is, and what steps have you taken to correct the problem?"

what would you say?