I have been polygraphed by more than one three-letter-alphabet-soup government agency.  I won't say which agencies, because I know they are reading this board so I want to try to keep some anonymity.  The fact is, TLBTLD: antipolygraph.org/lie-behind-the-lie-detector.pdf tells the truth.  All of my polygraphs followed the same format.   

Rule #1: DON'T CONFESS TO ANYTHING!  Don't snitch on yourself.  The poly is a scare tactic, nothing more.

Federal agencies are not God.  They don't know everything you have done, they only know what you or your references tell them.  If you paid for hookers, did drugs, committed a crime, or something and there is no record of it and nobody knows but you, then it never happened unless you tell the gov.  Keep your mouth shut.  The whole point of the poly is to get you to confess.  Even when the polygrapher tells you that you are having trouble on a question.  This will likely happen on the "crime" or "drug" question, or if you have traveled oversease or something it will also happen on the "foreign association" questions.  This is common, as these are cover-all areas.  You will never see your charts on the computer screen that the polygrapher is looking at, even if you FOIA/PA your file that part will be censored.  As far as you know, the polygrapher could be playing Solitaire or some other computer game the whole time during your session.  Just say you have nothing to hide and you'll be fine.  Say you are nervous.  They will tell you that nervousness has nothing to do with the poly results, but that is BS.  They monitor your breathing, sweating, nervous shaking, and are even watching your body language.  The real key to beating it is just don't confess to anything.  If you must use countermeasures (CMs), use the mental ones described in TLBTLD.  The breathing and other CMs are too risky if you are new to this.  Nobody can read your mind.  If you are pressed to confessions, then confess to minor stuff like traffic violation tickets you got, or taking paper from the supply cabinet at your job.   

The key to passing, or beating a poly is to just relax and understand that nobody or no machine can read your mind.  They can only read bodily functions which can be attributed to anything.  Don't confess to anything.  Even when the polygrapher tells you get stuff off your chest, don't give him/her the satisfaction of a big confession.  Confessions give polygraphers "gold stars" and merit awards at their company/agency, don't let them get one!  Confess to minor stuff like I just mentioned or don't confess to anything.  Say you have nothing to hide.  Say you are nervous because nervousness DOES affect your poly charts, whatever the look like.   

The poly is a joke.  Thank you AntiPolygraph.org for this site!  You are doing a great service, keep it up!