Making decisions about complex problems isn't always easy. It takes practice and experience learning what sorts of decisions yield the best results. Problems that require you to act quick can be emergency situations, like knowing where the fire extinguisher is and grabbing it fast enough to put out small grease fire in the company kitchen. Other quick decisions could be if you are asked to take on a new responsibility and only given five minutes to decide if it's something you are prepared to take on. Going with your gut is a skill, and the more you learn to trust your intuition, the easier it can get to make these kinds of decisions. Demonstrate that you are confident and willing to sometimes take a risk when necessary.