Well, I don't have anything for you that you won't have read somewhere before but I'll tell you about the things that I did which I was glad that I had done!
I don't know if you're flying out of EWR or not, we started at LAX and changed there but one of the things I did was to actually go to the United cargo depot before we left.
It started out because I was so scared of getting the wrong type of carrier that I had decided to just pay their rip off prices and buy my carriers from them ( for 2 cats btw)
As it transpired, they didn't have any for sale (despite me calling PetSafe to verify that they would have them.

)
So, I had to buy them somewhere else anyway but I took them to United along with the measurements (getting those was a job in itself, everything is a game with our cats!

) so that they could OK them.
They were pretty disorganized there, but helpful too if you know what I mean.
As the crates passed inspection I had them drill their holes right then. (They need to secure the door with zip ties and the drill holes are necessary for that) I was glad that I'd done that as the drill was pretty noisy and I think might have freaked the pusses out, had they been in the carriers at the time.
I mentioned that I'd not managed to find appropriate dishes yet so I was actually given (no charge!!!

) 4 dishes, 2 for food and 2 for H2O. The girl told me to freeze water in the dishes and put them in the carriers just before I left. Brilliant!
I also clarified the paperwork with them which put my mind at rest as I was still pretty confused at that point.

One other really good thing that came of my visit was that I learned from someone waiting in line that although the USDA (Hawthorne) is open until the end of the day, the vet is only available to sign the forms until 11 am so I had to plan 2 days for the whole vet visit/USDA visit thing as I there just wasn't time to get them both done same day with the drive involved from our vet to the USDA office.
And of course, once I'd been to cargo, I knew where to find it in the middle of the night when we were actually leaving!
Do fax your paperwork from the vets office to the USDA and wait for the confirmation that it's all in order. Our vet had made a small omission and I was able to have it corrected while I was there and save myself a trip. Time is precious at that stage in the game.
I read that someone had put an old t-shirt or similar in the carrier with their dog so that the familiar smell would comfort the animal. With our cats, I went the catnip route to get them used to the carriers, they went from being terrified of them to practically living in them, in one easy step!
Oh, another thing. Get to cargo EARLY on the day of departure. Don't listen to what they tell you. Petsafe told me to be there 2 hours before the flight! I'm like, I'm flying too and I have to be there 3 hours before as it's an international flight, how's that supposed to work?
Them..hmmmm ok then get there 3 hours before, Me, then I still can't get to the airport myself in time. Them, hmmm, just don't be there too early. Me-OK thanks so much for your help!
I went 4 hours ahead and was the only one there at 2.30 am. It took me a full hour to get through the process. If I had happened to be second or third in line, even allowing 4 hours, I would have been freaking out!
For some reason that I'm not quite sure of, I didn't worry at all, not one bit, about my cats during the trip. Well, maybe because my main concern was that for some unforeseen reason, they would be refused and so once I had them checked in, I just had no more worries left. (Does this make me a bad mum?!)
The cats are fine thank you!!!

The old girl got out of her cage, stretched her legs and went promptly to her litter box. She had seemed really pretty unconcerned.
The young one, although a really tough little cat was a bit more scared looking and she was really stiff for the first couple of days, evidenced by her walking a bit funnily. I imagine that she just stayed in the same tight little ball that she had been in when I left her at LAX. That soon wore off though and she's having the time of her life now exploring her new home.
