Sometimes its difficult to think through all aspects of an app or feature. An approach I've found that works well is to write the FAQ while still early in the idea stage. It seems counterintuitive since the FAQ is often saved for the end of the project or better, until after there have actually been frequent questions.
Writing an FAQ while you're still formulating the idea is a great way to see what you're building through a user's eyes, think through how features should work, and reveal what's missing.
Here's a quick example. Imagine you have an idea for an app that will allow you to enter your favorite bands and then show you upcoming concerts near you by bands that are similar. The hypothetical FAQ surfaces the decisions you'll have to make. Writing the answers reveals when a solution is cumbersome, convoluted, or not even needed.
- Can I signup without Facebook or Twitter?
- How do I add a new band?
- How do I remove a band?
- How many bands can I add?
- I can import bands from my streaming app?
- I added a bunch of bands, but I don't see any matches yet?
- How do I save a concert I want to see?
- Can I purchase tickets in the app?
- How do I share a concert with a friend?
- How do I turn off notifications for new concerts?
- How do I delete my account?
If you're a developer, you know this is somewhat similar to user stories. I think the FAQ-driven approach works great earlier in the process, when you're still formulating the idea. It's also a gentle way to introduce user stories to people on your team aren't familiar.
Starting with the FAQ before the product is fully formed also reminds me a little of test-driven development, where you write the tests that your code will need to pass before you write the code.
The tests in this case are the expectations of the people who will use your app or site. The earlier you starting seeing your product through their eyes, the better.