There are many ways to approach getting a wrong answer when reviewing a WK item by doing a “deep review” of the item. For example writing the item by hand, using the item to make a sentence (if appropriate), looking up the item in a dictionary, etc.
But I think a very important and often neglected step is to take the time and pay some respect to the Mighty Crabgator! Think about it. That is what he is here for, and his one and only task - to force you to review the items that you do not know. It is when we get an item wrong that we really have the opportunity to learn, and when we really do learn. Otherwise, we could just develop a sort of a feel-good Want Kani like application that just quizzes us on ありがとう all day. What we really want to learn are all of the items that are difficult for each of us personally, for whatever reason.
So stick with your reviews, use the above understanding of the process to prevent yourself from getting frustrated and 頑張ってください。