Anatoly has posted an example regarding orchestration and collaboration, and he has two particularly good pieces of advice at the end, though the whole post is worth reading:
Rule 1. If your attempts to model a process are unsuccessful because some significant aspects are missed repeatedly then stop and think - maybe in fact it?s not a single process but two or more?
Rule 2. Do not overuse collaboration - stay within the orchestration as long as possible. Never introduce collaboration into a diagram just because you?ve recently learned how to do that.
Both of these are excellent.? Rule #1 is exactly how I approach splitting something into multiple processes.? Rule #2 is just a good rule in general for any piece of functionality you're not overly familiar with, or any advanced functionality.? Start with the basics, and only go to the more advanced features when you clearly need to.