Brainstorming is a necessary skill leaders must have in order to promote creativity & innovation in the organization.A brainstorming session is relatively easy to do, but to make it an effective one requires some knowledge. An effective session means a lot of ideas are brainstormed. Anyway, to do one, you at least need to know the 4 rules of effective brainstorming.
Focus On QuantityNo, need to care about the quality of it. You can filter the good and bad ideas later. No use filtering ideas when you have only a small amount of ideas. But when you have a lot of ideas, that's another story.
No CriticismDon't try to show you're so smart. If you're really smart, give ideas la. When you criticize another person's idea (no matter how 'polite' you are), the person won't be so eager to share more ideas because he's afraid or shy that he might make more mistakes. Also, understand that every idea can lead to another idea. Do not shoot down the idea so soon, maybe some parts of it can used. If you reject the whole idea so easily, you may lose the chance to use a portion of the idea, and will have less ideas to modify or to think about.
Unusual Ideas Are WelcomeWe are conditioned in our mind to play safe, never challenge the status quo, follow the herd mentality. This does not create new ideas or innovation. So be brave and give unusual ideas. Something unusual at first can somehow be re-made into something practical but still innovative. Again, your objective for the brainstorming session is quantity not quality.
Combine and Improve IdeasI said before that ideas can change as long as people openly communicate, how? Because as more people give input, ideas tend to mix around, modified and change. I have stated before that editing & modifying is the 2nd stage of creativity. So, don't limit yourself. If the idea is not good enough, use parts of it that you think you can use.
Please apply the rules strictly, as ideas by nature are hard to come by. Ideas needs the right culture and atmosphere for it to materialize itself. A culture of insecurity or inconfidence does not promote innovation & creativity. As a leader you are the person to create this atmosphere or otherwise.