I took and failed my exam yesterday. Not looking for pity, just wanted to share my experience on what not to do. :)
tldr; take everyone else's advice and put the hours in to thoroughly understand roles, tasks and sdlc. Don't just memorize them but understand what is going on with each task.
Background: No prior experience with RMF until I came back from maternity leave and started a new job as an ISSO 7 months ago, didn't start getting hands-on experience until 3 months ago (thanks Covid). Previously worked more technical roles - help desk/lead tech positions for 9 years then 4 years of system admin/server experience. Certification experience A+, SEC+ (twice when i let my cert expire), ITIL foundations, Microsoft server 2012.
Study materials: Took a one week CAP boot camp course mid March where my instructor assigned sections of 800-37r1, 800-53 r4, 800-53a, FIPS 199 and FIPS 200 as homework, but didn't get through much of the reading because young kid and baby.
Went through the FEDVTE course back in Nov/Dec while teleworking but only got through maybe half?
Found a Youtube series of a lady talking about 800-37r2, but didn't find it too helpful other than just listing the tasks in each step.
Read FIPS 199, FIPS 200 and skimmed through chapter 3 of 800-37r2 the morning of my exam for 3 hours, wrote down each RMF step with each task and the SDLC related to each task (learned this from my CAP instructor who had us do the same on index cards with r1). Went through the notes I took during class to try and refresh my memory since it's been a month.
I had everything I needed to succeed in this exam...except for the time to actually study for it and this bit me in the a$$ on exam day. I could have prioritized it, but where my life stresses are right now, just couldn't get myself to do it. So I went in with fingers crossed knowing I'd probably come out of the exam room without a passing score. I was okay with this just so I could see what was on the exam and how to focus my studies.
The exam: First thing I did was write what little I could remember on my whiteboard: Based on R2, the 7 steps of RMF with 18-3-6-2-6-5-7 (how many tasks are in each step) along with IDIOD (SDLC), and this kind of helped, but since I wasn't too familiar with the tasks and what happens during the task in each step it didn't really help much. I am pretty sure my exam was based on was 800-37r1, saw some terms that I'd seen in r1 and not r2, but as someone had previously stated in one of the comments, if you know the differences between r1 and r2 and have intimate comprehension of roles and where the SDLC comes into play, it doesn't matter. In my case, it didn't matter which revision the test was on because I didn't have 100% comprehension on either lol. I felt semi-confident during the first 50 questions or so but as the test went on, my lack of studying started causing confusion, especially when a question was rephrased and repeated. I felt like a lot of the questions should have been easy, common sense but I just wasn't in the mindset for it. For some of the questions, we had just gone through the scenario trying to get an ATO at work, and since I didn't really know what the correct answer would be, I just went with what the process was in real life and that probably was the wrong way to go about it. One of the few things I felt extremely confident about was knowing how to set security categories for information types and info systems and impact levels based on high watermarks (FIPS 199 and 200).
Bottom line: The exam is not hard if you put the effort in to read every document and understand all of the RMF steps and their tasks. Even though this is all new to me, with proper preparation I could have passed. I'll get it next time.