Use the 5 Whys exercise to determine if a project continues to support its root motivations.
Every project must start from something -- an idea, a challenge, a requirement. But how do you know that project is the right project for your situation? How do you know that it will serve the idea, solve the challenge, or fulfill the requirement?
One approach I like to take is using the 5 Whys method to question the purpose of a project. The goal is to determine the extent to which the project supports its root motivation. Going through this process can occur either before the project begins or after it's already underway, as it's never too late to ensure you're working on the right thing.
I'll give you an example (as a requirement) that I hear constantly in my industry -- Build me a new website. Let's step through the five whys exercise (from the client's perspective) in response to the requirement:
In this case, the client thought they needed a new website, but the new website wouldn't have made them happy because it wouldn't have solved their root problem. If writing successful blog posts is a measure of the success of their website, then they first need to figure out how they can make writing those articles a priority. Otherwise any iteration on the website will fail to achieve what they really want.
You can work through this process with any project. Challenge your challenge, idea, or requirement by asking why until you get down the root of the situation. And if the project supports what you find at the root, great! Get started or keep going with it. If not, it might be time for a conversation about adjusting your focus so that it serves what it really ought to serve.
Try this first with your current projects and see if you can use the results of the exercise to better focus your efforts and keep you and your team supporting the projects' root causes.
Until you've had enough practice, it's terrifying to perform in front of a room full of people.