Regarding drivers, my strategie would be not to renew the contract to a driver who didn´t get where I expect. The biggest mistakes from MY point of view is what Honda and Toyota are/were doing with Button/Barrichello and Trulli/Ralph Schumacher and what Red Bull is doing with Coulthard.
To me, the drivers are the ones who pushes the engineers the most to make succesful cars, not viceversa. Schumacher and Alonso as themost recent cases. Then there are drivers who are extremely fast, but doesn´t help to develop the car as much (Raikkonen, Hakkinen).
I conclude this analising each driver with his team-mate. When engineers design cars taking into account "pushing drivers" input, they perform much faster than their team-mates.
"You need great passion, because everything you do with great pleasure, you do well." -Juan Manuel Fangio
"I have no idols. I admire work, dedication and competence." -Ayrton Senna