When you want to park your car don't put the gear shift on P directly first let the car totally stop while you holding the car by the front brakes shift to N now while the car not moving pull the hand brake now the car weight is on the brakes now you can put it on P .

Shifting at low rpms this might be difficult because you need to lower the rpms before the car shifts to the other gear by listing to the engine and feel the car going to shift i believe its better to shift at lower rpms it prevents metal wear but anyway since the x308 xj8 not sport car i think most of us wont go beyond 3 k in normal driving conditions .

I personally lowering the the rpm below 2k when car need to shift of course in normal conditions

Now this may work and it may not but i keep trying to stay away from problems with my zf5hp transmission

 

Longevity tips are to have it serviced(fluid,Trans-Go kit).