Stand up.
Pretend you're holding a spear in your hand.
Then pretend you are throwing the spear to the top of a roof.
As you are in the swing, pause.

there. That's the ideal posture, I think.

For all my homies out there busy bench pressing, don't forget that if you don't do any back exercises, your chest will just give you a hunch. And for all my computer scientists dudes, you need to counteract all that time spent leaning over your keyboard into your screen. Fix that posture!

If you can hold that spear stance while walking, that's good.