Any tips for long haul flights

What others have said plus comfy clothing, layers, slip on off shoes. Consider carefully where you would like to sit, prebooking seat if possible, aisle seat or window depending on whether you want to be able to get out easily or sleep undisturbed. Noise cancelling headphones work well, downloading your own podcasts or books prior to flight or watch provided films.Take your own snacks and buy/ fill up water bottle when through security. In flight food is not always that great and I find there is never enough water. Best to have eaten before you board. Lights out time and meal times will be decided by the cabin crew.

I hate long haul flights so when I went to Australia I took a sleeping tablet, my husband said I was snoring so loud people were laughing and looking around to see where the noise was coming from.
He said he didn’t know weather to wake me to stop the noise or let me sleep to stop me moaning, he decided on the latter

I've never gone on quite such a long non-stop flight but here goes:

Do foot and leg exercises and get up and walk around too. Drink plenty of water (it should be available so you can help yourself). Fruit should be available as a snack as well as meals.
Films are ok but take something to read and puzzles eg crosswords as it can get boring.

Comfy clothes with a warm cardigan, take some clean ones in your hand luggage too. Clean off your makeup and take a small moisturiser. I'm not sure if they provide a toothbrush and toothpaste now but take them just in case. A small or blow-up neck pillow is a good idea.

Enjoy your trip!

Loose shoes that you can kick off. Music of your choice and earphones. Keep alcohol to a minimum! It is hot in Perth so layered clothing you can take off.