A preconceived notion can be poison to improv. I don’t mean coming in to a scene with an idea or inspiration. That should be encouraged. I’m talking about walking on stage determined to do “this kind of show” or “this kind of scene.” There’s no way to know the situation will present that.
The first thing an artist does with a bonsai tree is to look at what he has to work with. That determines where he goes. Similarly, you should take a look at your show after the first few scenes to see what kind of show it is. Will it be fast-paced? Will you rely on a few slow, building scenes? What has already been established in this world that you can use later on? Be frugal. Use the ideas you discover in those first scenes. They’re good ideas!
If you open a box from Ikea, you may have the parts to make a chair. Why try to build a racecar? Look at your parts. Build that. Don’t try to make something that isn’t presenting itself naturally.
Similarly, a bonsai artist carefully prunes and bends a tree over time. He doesn’t chop it in half and screw the parts back together. Make sure any attempts to “steer” the show come gently enough to allow for continued growth. While you may discard some elements of the show that don’t work, be sure to retain those that do.
And finally, the bonsai artist begins with a tree, not a seed. Likewise, your team is already composed of human beings with many preformed ideas, patterns, physicalities and energies. Be sure to choose a form that highlights the best parts of you. And if it bends mid-show, follow the bend! When forming a team, if you have great shortform players, embrace that. If you have physical players, work to heighten that strength. Don’t bother trying to put a human-shaped sweater on an octopus.
Discover who you are. Discover what your show is. Be that. Let it grow. Prune carefully.