Because practice questions are so critical to effective Step 2 CK prep, make sure that you are using your UWorld question bank in a way that most closely replicates real-time exam conditions. This means using timed mode and randomized, mixed blocks as you get more familiar with Step 2 CK-style questions and test items.
Initially, you will want to do subject-specific blocks to get familiar with and master the concepts tested in each subject area, but later on, you should transition to randomized, mixed blocks.