The decent planning is the most important thing. you need to understand the amount of heat that the turbo is producing to realize why it's so important. on C402 at night you can often see the turbo glowing orange. hence take extra caution on decent.
don't forget to always park into wind after landing to take advantage of the extra airflow through the cowl.
On long taxis keep an eye on your temps, if you have to hold for a long period, turn into wind on the taxiway.
High oil temps cause the waste gate to not operate properly on some engines, usually you will notice full throttle being 1-2 inches off where it should be.
Lastly have a chat to your LAME about your particular engine and understand how the turbo system works. It could make a big difference one day when the donk starts making silly noises.
As for efficiency, you only get the extra value out of a turbo aircraft at higher altitude. try to cruise at 8000+ where you can.