Based on what I've seen on the scores threads for the past ~3 years, it's evident that people can get high scores doing a variety of things. It's not so much your exact study materials that's important as much as it is the way you consolidate toward the end. As long as you finish the gold standard resources (FA + UWorld), whether you choose to do Rx, Kaplan, Pathoma, Firecracker, Microcards, etc., is really just up to personal preference. People have aced the exam using resource permutations of pretty much every type. The one thing all high scorers have in common though is that they used FA and UWorld at a minimum.
#1)
Go in rested. Being well-rested will get you more points than sitting the exam tired having studied for two additional weeks. Why? Everyone makes stupid errors. It's really rare for someone not to. Even people who get the top scores know of a question or two they screwed up on. The bad news: your absolute score decreases. The good news: everyone does it, so relatively speaking, the errors cancel out; if you're high-scoring though, a single stupid error equals more points than at the lower range (i.e., a 261-264 might be one question, depending on the form, whereas three questions might be 218-220; not every score is possible on every exam). I have a friend who had two 270+ NBMEs who got a 259 on the real deal. Sleep, and you'll cut down on your errors.
#2)
Calibrate toward the NBME question style and don't over-think things. The last questions you do should be NBMEs, not UWorld. The NBMEs are the USMLE. Those are USMLE questions. And if you add up the NBME exams (200 Qs/test), they're essentially a QBank. Look at the NBME questions you get wrong and analyze
why you're getting them wrong. Did you not know something? Was it a stupid error? Did you over-think? The latter is usually the case. UWorld trains people to over-think. You'll find quite a few of the questions you get wrong in UWorld were because of some sort of trick. But the NBMEs, in contrast, are very straightforward. If you get an NBME question wrong, it's usually because the presentation was a bit odd/strange, but they weren't tricking you. For instance, you might get a case of septic shock where the bicarbonate isn't low, or a case of pulmonary embolism where the patient has mixed metabolic acidosis-respiratory alkalosis, instead of just respiratory alkalosis. I've got my 2CK in two days. I made it a point to be done with UWorld and solely focusing on the NBME questions during the final ten days.
Before I sat the Step 1, there was a guy on here
@MrBeauregard who really hammered into me not to over-think things. And it saved me on the exam. Sometimes the answer really is just Cryptosporidium parvum. Not Isospora belli. Cryposporidium parvum. Don't over-think things. Go with your gut. And you'll be fine.