It depends on the question. For instance...during a job interview.. ask the question back to the interviewer. This gives you time to think of a concise answer. In everyday life ..again depending on the question.. take a moment to decide if the person is really asking your opinion.. or if they want a quick answer. I have learned (and yes this takes practice) to answer yes or no.. then ask the person what they think. For instance .. Q-"Did you see the movie?" A- "Yes, did you like it?". This can lead to a discussion that is not one sided, as well as giving the person a feeling of being valued for their opinion.. even if you don't agree.
Hope this helps!