Insight Maker is completely web based making it easy to develop and share models, allows concurrent multi-user editing, and just happens to be FREE, which a pretty good feature/price ratio.
There are a number of habits that one should practice to improve their Systems Thinking skills. This graphic is from the Waters Foundation Systems Thinking in Schools site.
The intent of a Systemic Perspective is to provide an appropriate level of understanding to support the development of a strategy for dealing with the situation while also providing a level of confidence that implementing that strategy will not result in a myriad of unintended consequences which simply make things worse.
There are a number of habits that one should practice to improve their Systems Thinking skills. This graphic is from the Waters Foundation Systems Thinking in Schools site.