Here is my piece to give back to so many who have helped me. For reference, I am a DO student in the top 15% of my class.
Uworld 1st pass: 71% (was getting ~85% in the last few weeks)
Uworld 2nd pass: 93%
NBME 17 (baseline): 210
NBME 18 (1 month into dedicated): 225
NBME 16 (1.5 months into dedicated): 240
NBME 15 (3 weeks out): 250
NBME 19 (2 weeks out): 255
UWSA 1 (2 weeks out): 265
UWSA 2 (1 week out): 260
USMLE: 250+
COMLEX: 800+
To start, I will echo what many others have said. The absolute MOST IMPORTANT thing one can do to prepare for these exams is to study well during your first two years of medical school. There is absolutely no substitute for this. It seems that many students (as we all would), want the easy answer on how to get amazing scores on Step 1, but the true answer is hard work. I must say that I am still in a little shocked about my scores, because I still doubted myself even though practice scores estimated me in the ~250 range. However, my point is that despite the doubt, I worked my ass off every single day in order to get to where I am. I sacrificed time with friends, family, my wife...etc. All of that time I could have had was spent learning the material and that was BEFORE dedicated period. I do not write this to discourage students who are now looking upon this at the start of their dedicated time. I write this to try and grip the incoming 1st year student about what rigors are necessary to succeed on Step 1 (unless you are just some god-sent genius). Again, there is absolutely no substitute to 2 years of hard work and study when it comes to these exams. For those who did not put forth their 100% during the first years and are now finding themselves needing to kick it into high gear for dedicated, just use it as motivation to work that much harder. You can do it!
Second, another very important thing that I did was that I made a study plan that I WAS ABLE TO STICK TO, with enough wiggle room to fall back on if I needed it. This was probably the most important thing that I did during dedicated that was not related to actually studying. This allowed me to stay calm and not get overwhelmed if I would get behind, and it allowed me a chance to catch up when needed. Start the process of making this EARLY in 2nd year so that your dedicated time does not sneak up on you and leave you frantically running around trying to figure out what you want to do. I can honestly say that I would not have done anything differently with my dedicated time because looking back on what I could have improved on is only something that I now see due to hindsight, not because I would have realized them in the moment or that I didn't put in 150% every single day.
My study materials: Uworld, FirstAid, Pathoma, SketchyMicro/Pharm, and a couple Goljan audio lectures (let me use this opportunity to reiterate that the largest and most important study material that I used was the FIRST TWO YEARS OF SCHOOL). I also used Savarese ("green book") and COMBANK OMM questions to supplement for my COMLEX exam.
I really felt that the above materials very well compensated for the basis everyone needs to know for Step 1. The remaining effort is up to you to make the connections necessary to understand all the information. My advice would be to buy and get a grasp on these study materials around December of 2nd year. Become familiar with them so that, again, when dedicated time sneaks up on you, you are not frantically running about deciding what to do. While I found these resources adequate for my personal learning style, YMMV. I went through Uworld two full times during dedicated, but started my 1st pass around March. Getting through Uworld was a slow, arduous process, but in the end it does incredible things for one's understanding (in my opinion). Going through Uworld slowly the first time really allowed me to make the necessary associations and my 2nd round was just for reinforcement. Questions really are the best way to learn the material. Additionally, I don't feel the need to go into each resource individually and how I used it because that is really up to the individual and these forums are full of people repeating themselves over and over again about them.
Lastly, make sure you are taking a step back from studying for Step 1 once and a while to actually enjoy life for a bit. Every single Saturday of my dedicated period was a 3/4 day off that I would spend with my wife and I would not trade that time for any higher score. It is so important TO KEEP YOUR STRESS TO A MINIMUM while you are studying, because having a breakdown around exam time is about the worse (non-emergent) thing that could happen to you in terms of your performance. The USMLE was one hell of a test; beyond difficult. But, I was able to stay calm throughout the entire experience and minimize my silly mistakes. In fact, many times on the USMLE did I find myself going back and changing an answer to the correct one due to catching some stupid mistake I made. It is much harder to do this when you are an anxious wreck.
For the COMLEX/USMLE comparison, I felt that the COMLEX was a much more straight forward exam and that my preparation for the USMLE adequately prepared me for the COMLEX as well. Reading Savarese and doing the COMBANK OMM questions was more than enough (for my exam) in order to do well on the OMM questions. Do not make the COMLEX more complicated that it needs to be. I would encourage to use the strategy of taking the USMLE first and then the COMLEX 3-5 days afterward in order to cram OMM. Do not let anyone else tell you otherwise. I vividly remember a bunch of my OMM faculty always spouting off about what would be necessary to prepare for the COMLEX and it is all just nonsense. Use the COMLEX blueprint if you must, but I felt Savarese/COMBANK was very adequate.
I want to send a personal Thank You to all the individuals who have been so supportive to myself and all the other students as we go through this process. Hopefully I can leave my mark in a similar fashion. I would be happy to answer any questions/PMs if anyone is in need. I wish everyone the absolute best!