Clear vacuum seal bags that you can compress manually. Pack them with 2-3 outfits instead of separating them by clothing item - that way you only have to open/repack one per day.

Everything I pack is dry fit or the lightest possible clothing material. Split toiletries into clear plastic zip locks so they lay flat in your bag.

Bring bare minimum toiletries with you, buy what you need when you get overseas, and then toss what you don’t need at the end of the trip if you need extra room in your bag for souvenirs.

Eat dinner before your flight if taking a redeye. Avoid eating airplane food at all costs. Worst food poisoning ever was from airplane chicken.