Repeat the question when getting it wrong before advancing
I often hit next before fully taking in what I did wrong - it's just instinct!
It would probably help me a lot if after being shown what I did wrong, the question then resets and I have to put the correct answer in in order to go to the next question.
Obviously you wouldn't get points and this might not happen during the timed quizzes.
I think it would go a long way towards making things stick and keeping the correct answer strongest in my mind.