Know that not everyone is satisfied with the material in the EK 1001s. I've heard good things about physics EK 1001, but that's it.
The 1001s author advises the user to do every 5th question, that way the user gets to touch on different question areas. If you find yourself getting all the questions in a certain area right (i.e motion problems), then you're probably good to move on from there. But if you're getting a lot wrong (i.e in the fluids section) then that's probably a clue that you need to review the material, review the questions, and spend more time doing more questions in that section until you feel comfortable and confident to move on.