At the heart of good improvisation is learning to be aware and connected to your fellow performers.
Too often in life we don't really pay attention to the people around us. We are too distracted or busy to really focus on them. How often have you found yourself in a conversation with another person, where you are thinking of what you are going to say next while they are talking?
Unfortunately, this habit appears regularly on the impro stage. Performers, trying to think about where to go next in a scene, disconnect from those around them. They stop listening to ideas and instead turn inwards to find sources of inspiration.
But how can you create something with another person if you not open to what they are trying to communicate? One of the most important but often hardest lessons to learn as an improviser is to be aware - truly aware - of those who you are performing with.