You are only as credible as your reports. And, if you hang too many people out to dry, such as state's attorneys, then your credibility will be shot. The other lesson is working relationships. Actually, your written reports are one aspect of your working relationships. But in addition, there are a whole host of other law enforcement relationships which you must cultivate.
Any investigation requires the cooperation of others, both within the agency and among agencies.
For example, there are always overlapping districts. You must have an awareness of jurisdictions, where you are, and whose turf you are working. A crime is committed within a sheriff's department's jurisdiction. But it may involve other possible crimes and criminals in other locations, or you may even be involved in a pursuit. If you just ride in like the Lone Ranger or John Wayne you will certainly not get the needed cooperation.