Failing to get buy-in. As with any change in an organization, it's important to have the key players on board with the plan.
Ignoring the human element. Almost by definition, implementing workflow means combining systems and people. If the people don't understand the process, and its benefit, they aren't likely to cooperate enthusiastically.
Re-engineering the whole organization at once. While some approaches to improving an company's function, such as ERP, have to be applied to the entire organization essentially simultaneously, workflow is process-based. That means it's inherently bottom-up and it's easy to implement one process at a time.
You may intend to improve every process in the organization, and as you gain more confidence you may work on several processes at the same time, but starting small and building block by block decreases risk and improves chances of success.
"If you start with 20 or 30 processes you're missing out on the opportunity to learn on the job," says May.