Flashcards didn't work for my daughter at all. She just can't learn that way.

What we did for spelling and math facts was just to have her write each word/fact in the list X number of times (usually 5) and then we would quiz her on them. If she got them right, she was done. If she missed any, she would do them another X times. The rest of the week, we would quiz her each day before she started and she would only have to write the ones she got wrong. Usually she had everything down by Tuesday or Wednesday and her motivation was the progressively smaller amount of time she had to spend studying instead of playing.