Important caveat: just because electric toothbrushes are good does not mean “more power = better”. For natural teeth, you should always brush gently. Don’t go ham just because you’ve got a powertool in your hand!
If your brush has multiple intensity modes, always use the lowest. Same thing goes for your grip! The whole point of an electric is that it can get you clean with almost zero pressure. Seriously: apply no more pressure than necessary to get full bristle contact. It will extend the natural life of your teeth and gums by years.