Flying International First time - Qatar Airways

Hey fellow travelers! This is my first ever time taking a flight and I'm gearing up for an economy class trip and want to make the most of it.

I'm curious:

What items are we allowed to take from the plane? Are amenities like pillows, blankets, or headphones up for grabs, or should they stay onboard?

Any insider tips or hacks for flying economy? From seat selection strategies to making the most of in-flight services, I'd love to hear your advice.

Looking forward to your insights!