Hey no prob, glad to help out a fellow stringer... as long as he's too far from me to compete, that is...
Seriously, part of the reason you got scrammed from some scenes is because you showed up on stuff the news wouldn't care about. I know you're just testing the waters, but that's a dead giveaway that you're just a camera carrying looky-loo to them. So stick with the big stuff.
Another reason may be the way you present yourself to them. As for press ID, make up your own little company and then make up a photo ID for yourself. You work for "Houston News Video Services Inc." and you are onscene to get video for the news stations - that's all John Law needs to know. Also, don't go up and be all timid and going "hey....umm... I .. uhh... was wondering if.... y'know... I could.....shoot... some...uhhh video?" I made that mistake early on and the cops knew I was a total noob. These days (even if I just have a consumer handycam in my mitts) I stroll up and say "Media - where do you want me?". Sometimes they look at the camera and go "Media? With that thing?" I just say "Yeah I know. It's my day off, they told me to just get here quick and shoot what I can on this thing." Works like butter on biscuits...
As for formats, that's up to the stations. As soon as I get a better cam, I intend to get some webspace and host my stuff on a webserver for the stations to download. It may work, it may not, it depends on how technically savvy they are and how easy I make it for them. Still in the planning stages there - until then I come in to each station and dub the damn tapes, get a signature on my invoice, make a copy for me and submit the original....yawn. It's a pain, but for you this would be good because you can get to know the staffers and get some pointers for "the next one".
What headaches do you get from the desks.... ohhhh boy, you are new aren't you?
Mainly the one I get alot is "Oh so and so called us just before you did and he's already there." Total BS, so and so just charges less than me. He shoots like crap, he lies about where he is and what he has. It's a real pain. The deskies know that, they know he lies, they know he sucks, they know he's scum and THEY STILL BUY HIS VIDS!!!! ARRRRGH!!!
Another one you'll get alot of when you're new is "hey, go check out such and such." Most of the time, such and such is over an hour away and either: A. Over when you get there or B. Never existed in the first place.
There's more but that will give you some thoughts to ponder. As I said, this is a fun business, but there are times when it can downright SUCK to be a stringer. Overall though, I love it.