I understand handshake agreements but it’s better to get everything in writing. Make sure your project has a clear timeline. What will happen if a deadline is missed? This street needs to go both ways because it’s not always the company that’s dragging its feet. Nonprofits can be notoriously bad at allowing endless discussions to delay decisions.
Make sure there is a clear understanding about how many revisions can be made to the project. Does one side consider a revision to be fixing a typo while the other believes it means starting from scratch?
Will your assignment, like a a website, be based on a template? There’s nothing wrong with using something that’s been successful in the past. The downside is that when you use a template, it looks like everyone else’s website. Keep in mind that original work costs more.
In all of these scenarios, don’t worry about being demanding. You represent your stakeholders and they trust that you’ll make a smart investment. Take that responsibility seriously.