A collegue of mine told me that the best way to see the ineffectiveness of a business process is to place it on the web. If your business processes don't work - it doesn't matter how great your website looks or how well you've marketed it, you won't succeed. It's an interesting thought. Which leads me to think that probably one of the best approaches to figuring out how to design business processes is learn how to create Customer Scenario Maps.
The Patricia Seybold Group defines scenario mapping as " a way to quickly discover and communicate a context-rich set of customers’ ideal requirements" (from the Patricia Seybold Group web site). It's a requirements session completed in a visual manner that requires you to think like your customer. And it's a fun way to gather requirements.
Several years ago I had the opportunity to meet Patricia Seybold and another consultant from her firm - Ronnie Marshak through a company I worked with. We spent a day long workshop with the two consultants and learned the basics of creating a scenario map. It's called designing from the outside in and it involves taking the time to really understand who your clients are, what their needs are and how they interact with you. It's definitely about more than the web - there are many ways a client can approach your business, but walking through this process will definitely help you understand how to design your website and the business processes required to support the site.