We bought neck pillows and sleep masks at REI before we left. I have discovered that the trick to neck pillows is not to over inflate them. That's easy, because they inflate so easily with your breath. And every instinct says make them floatable.
But if they hold your head too far off the back of the seat cushion, your head falls back into the space between it and the cushion. That's what the adjustable seat pillow is for - to place your head upon. But it's too hard. So the answer is to underinflate your neck pillow, slide up the seat pillow to it's highest point, and tuck your head into the bulk of the neck pillow under the seat pillow. It works, believe me.
Now for the sleep masks. The sun goes down here at about 11pm and comes up about 3pm. Unless you can sleep solidly through the night, you're bound to wake up to a bright room. With my sleep mask on, Pat said I look like one of the panelists on the old "What's my Line?" show (the funny woman whose name we can't remember).
It took a while to learn how to use the sleep mask. The problem was eyeball pressure. If you put it on like you would imagine it should be, the tension put too much pressure on my eyeballs. The solution was to place the band section up on my eyebrows, aim my chin down into my chest, and cover the nose gap by putting my hand under the pillow to create a hill between me and the window. When I gave up an hour later, and gave it to Pat when she awoke briefly (hers was lost somewhere in the attempts to sleep on the flight), she showed me that the strap was adjustable, and soon wore it to sleep. Note to self: get another one with an adjustable strap, and try again. I remember sleeping on the beach in the hot sun as a kid after a long morning surfing. I think the trick is to be very tired.