Hi, this is an industry association, so I assume this question is related to running a business? If you want to know about how to grow a healthy plant, there are lots of hobby grower forums for that. First timers should not be starting commercial grow operations without experienced growers.
In any case, there are certainly plenty of mistakes to make along the way with a commercial operation, starting with site design and continuing on into chosen cultivation methods, pest/mold prevention, and efficient allocation of the labor force.
I'd say the biggest misconception that investors and entrepreneurs have related to cultivation is that cannabis can be "widgetized" - that a certain set of rules can be followed for reliable repeatable outcomes. That's only true to some modest extent. People forget that plants are alive and thus do not behave like machines, and they go into cultivation businesses having no idea what they are actually in for.