It’s easy for any improviser to forget, after all the hours logged in classes and on stages in front of audiences, that they once started out as sweaty-palmed students. Whether you’re brand new to improv or you’ve been performing for years, I want to remind you all of the Squirrel in the Garage: the thing that will awaken you to your imaginative side, or the reason you started improv in the first place.
The honest-to-god simple answer is to stop having ideas.
Ideas are fun, and they can be useful. But they’re only one part of improv.
Instead, just react.
Actually look at your scene partner in the eyes and have a feeling.
Trust that enough reactions strung together equal a scene.