Do break-in only when your car has less than 5 miles on it. If your car has more than that, chances that it was being a test drove for a Joy ride happened. You know how that goes....usually they will red line it out every time they have the chance.
Break in idea is to have the Metals down to micro size to be smoothed out, that includes the uses of oil being used. So if you break-in with that oil brand, always stick with it.
Another thing is the Temperature of the engine, slightly increase it, then cool down, rinse and repeat. This will get the Metals to get Used to the Fluctuating Temperatures, after a while the Atom structures will be set, so it will not easily crumble or crack.
1/ Idle to warm, shutdown to cool.
2/ Idle to warm, drive for 5 minutes @ low rpm+speed. Shutdown to cool
3/ Idle to warm, drive for 10 minutes @ higher rpm+speed. Shutdown to cool
4/ Rinse and repeat. Gotta keep it below max torque RPM range to avoid stress, strain.
keep doing that until 350 miles. Now the engine shall be ready for rapid powers, speed, rpm, loads. Drive like a maniac for another 650 miles. Now you are done breaking in
And I am not joking about driving it like a Maniac, you have to do rapid acceleration, Deceleration, Red-line, Loads. That is to make it used to all the stress and conditions. Voila.
But as how complicated a proper break-in is....just let it fly, because chances are most of them was test drove on