I found a lecture on YouTube given by a former USAF and CIA employee who is now a lawyer who specializes in clearance law.
He gives a very nice summary of the process with a focus on adjudicative criteria and the do’s-and-don’ts of filling out the SF-86. A lot of specific examples are provided that I feel would help answer a lot of the types of questions people ask on here.
The presenter was a contractor engineer for Air Force and CIA. The majority of his information is very good but is still a engineer turned lawyer view of the process.
For instance, instructing the investigator to list non-issue information or information not reportable just doesn’t happen. Though, if valid, it would be reported.
The presenter did have a lot of good and accurate information. This is a good, general, view from the outside of the security process.