I believe the best way to avoid scope creep is to define a scope and then stick to it. Any deviations should become new changes or projects separate from the one that you are working on. For example, in a project I am working on, a certain product needs to have its shelf life reduced on label. This would be a simple enough change however, after some analysis of the product, it was found that there are already product out there that if the on label shelf life was reduced, would immediately “expire” the product that is out there already. As a team on the project we decided since it was not in the initial scope of the project to continue the shelf life change and have another project be raised to remediate the product supply problem. In this, we stuck to our scope, and avoided having a mammoth problem being added to our relatively simple project.