Hi, it's hard to answer that question, and it all depends on what aircraft you mainly fly. Is it a jet, a helicopter, a small prop?
You mainly need to map it yourself in a way you find it logical, so that you remember easily.
But given the fact you have 4 axis, one hat and 12 buttons, you could be thinking this way :
the 4 axis will be naturally :
pitch, ailerons, yaw, throttle
The would most certainly be to pan or tilt view, whatever your prefer. I personnaly prefer to "pan view" from the keyboard, with the arrows for example.
The trigger could be for breaks (activated when pulled, avoid parking breaks here).
What's remaining is :
6 buttoms on the base
1 lateral button
4 buttons on top
So you need to prioritise and the most commonly used comands, for me, are :
-Flaps up and down (2 buttons)
-Gears up and down (2 buttons)
-Spoilers retract and extend (2 buttons) which would allow you to arm them too
-toggle reverse (1 button)
For the 4 remaining buttons, I would choose :
forward fast, backward fast (2 buttons to move the viewpoint)
ground speed acceleration X1X2X4 (or sim acceleration if you prefer) - 1 button only
another option could be : 2 buttons to move time forward or backward
But again, this is all very personnel, because I use the sim mainly to develop airports.
You might rather have start up actions like battery on, ignition on, lights on etc...
It is not yet possible to easily save and activate different profiles. I don't know if and when Laminar Research will implement that, but you might want to have a look at the plugin "X-assign" on X-plane.org
Hope this helps.