Personally, I was a huge fan of EK1001 for taking a concept and then systematically going through all possible permutations of the questions and approaches. For me, if I were stuck on one concept and found myself not understanding it quite well enough to shift gears and come at it from a different direction, I'd start there.
I would go through at least every ⅓ EK1001 for those subjects, not worrying about timing or when you check your answers, etc. At the end, however, you MUST sit down and work out, in as great detail as possible, exactly how they got their answers. The beauty of EK1001 is that all of their questions can be answered simply and easily...if you can see how they approach it. The answer explanations aren't great, but if you're willing to put in the handiwork, you can see the leaps they took to get the answers quickly. I would also recommend starring questions that take a long time or seem overly difficult as you go...even if you get them right, odds are there's a quicker way that could teach you something.
After you do that, go back and do the two surrounding questions for any that you got wrong. With the way EK1001 is set up, those two surrounding Qs will be similar to the one you missed, but with one or two tweaks. If you're still getting them wrong, you haven't solidified that approach/concept. Make flashcards for these (q on one side, no multiple choice options, answer on the other, with brief explanation if needed). I don't care how - Anki, quizlet, good old-fashioned cardstock - but do it. Go over them. Learn them until you can see that setup and just know how to approach it.
Maybe this won't work for you. After all, you're not me, so what worked for me may have no bearing on you. But this is at least one example of how to take a fully active-learning approach to mastering a topic you struggle with.
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