1. hope there's an invert option (not always!)
2. find an opportunity to change it (can't always do so before starting the game, nothing loses immersion like waiting for a cutscene to finish then immediately spending time hunting through a menu)
3. actually find it (will it be under gameplay? controls? somewhere else entirely)
Bonus: if it's a game with "grab the drawer then pull with the thumbstick to open it" mechanics, hope that they remembered to invert those too
Bonus 2: repeat the above for turning off controller vibration, which was also a global preference on the 360.
PC bonus: hope that the option does _not_ affect the mouse (I sometimes switch to mouse+kbd or mouse+controller, I never want to invert my mouse)
Yes, some games present the main brightness/control/etc. options when you begin a new save - but I don't know that's about to happen so have already spent the time hunting in the options menu...