Photo's got good points. The only thing I can add is this. (2000 hrs of 402C time here!)
Take-off...come up smooth until turbo's kick in. Pause. Then up to red line. Rotate about 90kts. Climb out at 120kts.
Climb out...power back to "top of the greens" on MP then RPM. Mixtures stay rich.
Level out...get on the "plane" then MP to 28", RPM to 2300, mixtures 100 degrees rich of peak.
Manuevers at 25" and 2300 RPM. Gives about 140-150kts.
Stage cool as Photo said, about 2" MP per 1000' of descent. (2min at 500fpm)
Approach...approx 20"-23"MP and 2300 RPM should give you around 130kts. Approach Flaps will take away 10 kts and get you around 120kts for appch. Gear is worth about 300 fpm descent or 30kts of airspeed so intercepting the ILS, throw gear down, pull back two or three inches of MP and you should be about 600 fpm, standard for most ILS'.
Trim wheel is by your right knee. I always rested my hand on my leg and trimmed by hand, even when I had electric trim. She trims up pretty good.
Landing...runway made, full flaps (don't go to intermediaries unless you're just doing pattern work. The damn things are all drag!) 100kts over the fence, touch down through 90kts unless it has VG's then you can slow her waaay down to nearly 75kts!
We've been instructing this way for years. Cools the engines, makes the math easier (120kts is 2 miles a minute), saves wear and tear on the plane and makes it easy to fly.
Good luck and if you have any more questions about the 402 feel free to pm me!
Eric