The hiring process is maybe the most ridiculously bureaucratic process I've ever seen... (no, I'm not exaggerating). They will interview and cross-check you and inspect everything about you and then they will STILL hire a person that is completely wrong for a job. I have had to hire many people in my time and it is a nightmare on BOTH sides of the process, if I know a person that has been doing the exact job as a contractor for years and is the best candidate... I can't hire that person if even one veteran or military spouse or transfer from another facility applies and has a pulse. I'm a disabled vet and I understand the need to give some preference to other vets and military families, etc... but it (like most things in the government) has turned into one, huge loophole for those that know how to play the system... those few that are honest, forthright and would be real gems for the organization aren't big enough "players" to make it in... there are some AMAZING people that work their hearts out every day, but for every one of them, there are 5 that are just desk-surfers. All that being said, (no angst here, eh?)... you CAN get into the system by religiously checking USAJOB and applying for everything you can... get in as a clerk if you have to and then move around within the system, once you are in, it is much easier to get what you want... not guaranteed, but easier.
A couple of other pointers... sometimes we post jobs for the minimum 72 hours on a Friday of a long weekend, hoping that nobody will apply except the person we know is best for the job... so check often. Also, when they ask for supporting paperwork of any kind, get it for them and if it isn't required but it asks for it anyway, supply a piece of paper that says something to the effect of: "This blank page is a place holder for form xxxx which is not required for this position"... the reason is: If a job asks for something like a "veterans status" letter but you aren't a veteran, it doesn't disqualify you.... BUT... if the system has that listed as a form you need to submit and you don't upload "something", then it automatically kicks you out of the process before a human even gets to see your resume.
Don't be surprised if your interview turns into more of a "let me tell you all about us and our needs" rather than being asked about your skill sets. Your average gov interviewer is usually not very experienced at all... they VERY often have never (or rarely) ever hired someone before, so they may be just winging it.
Remember, this is a nit-picky, pedantic process that is not even controllable by the person doing the hiring... so don't be discouraged or take anything personally... tenacity will eventually get you in the door... but remember, the process will OFTEN take 2 to 6 months from first submission to first day of work... (and often much longer).... yes, sorry, but that is how it normally works... (hence, the loss of the talented people to other jobs and the acceptance of those just waiting for a free government ride).... ((sigh))...