I did the egress course a few times.
Main things to remember if you have access to an exit next to your seat:
-Close your eyes!
This way it won't matter if you are upside down or not. Plus all kind of fluids may come in contact with them after the ditch, stinging you and renforcing any kind of disorientation you may have.
-Stay strapped until you open your exit door/window.
It keep your orientation good (even with your closed eyes)
It also keep your balance/forces to open the exit. Otherwise you will find yourself like an astronaut in orbit.
-Once your exit is open:
One hand on the frame, the other to unbuckle yourself.
Then you extract yourself from the wreckage in a single move and let your body find its way up.
Still want to open your eyes!? Swim up to the surface!?
One guy during training sessions had to get assitance because he swam like a mad man.....
Toward the bottom of the pool!
And twice!
Quite a feat with an helmet acting like buoy
(They switched all lights off those times, so much for keeping your eyes open to cheat!)
If you don't have access to an exit next to your seat.
-Same drill of closed eyes but this time you will have to unbuckle, find your way to one and open it.
--> If you start to float in the cabin, you Will be pretty much f..ked as you will loose your orientation <---
So practice to find and open your exits like a blind man would do...