I just completed a "self-assessment" prior to our exam (in reality this should be completed at least annually but I just assumed CRA responsiblities 1 month prior to the exam).
What I did was identify who my institution considered its peers and then who the regulators considered our peers and any institution that had recieved an "outstanding" in our region and pull their P/Es from the regulator website. I also reviewed our prior exam and recent minutes/documentation from the Bank's CRA committee to make sure I understood any goal (lending, investment, service) that the Bank had. This information could be housed in Board minutes, loan committee minutes and/or any other committee that may discuss these issues - you need to find it all.
Once you have all of the information, you need to gather your Bank's data (lending, investment, service) and start to analyze it. I used the charts that my regulator had used in the P/Es to determine what to look at for lending and benchmark our performance. For investment and service I benchmarked our "offerings" against the peers and provided a discussion document to management on where we needed improvements. (We didn't have time to prepare 2 documents so any "critisms" we handled outside of the document via discussion documents. Out of these discussion documents came goals for investment and service.)
Finally, I wrote a narative that explained the results. I also made sure to identify anything that made me different from my peers and to point out the unique atributes that my bank brought to the market.
The document was well received by management and the regulators. They basically used my document to create the P/E.
This was a major project and took most of a month, but the CRA exam was a piece of cake because the examiners had everything they needed and required minimal "hand holding".
Hope this helps.
The opinions are mine and do not necessarily reflect those of my employer.