You do not need a customer list or impressive numbers to make a useful page. Publish one real thing a visitor can inspect: a working prototype, a completed illustration, an excerpt from a newsletter, a small collection of resources or a clear invitation to an upcoming event.
If the project is early, say so plainly. “Preview the first three lessons” works when three lessons exist. “Join a thriving community” does not work when the community has not begun. A page can invite the first people in without pretending they are the thousandth. Link to a destination that explains what is available today and what is still planned.
Choose a cover from your actual work when you have one. If you do not, a clear title and message are better than an image that suggests a product you have not made. Ask a visitor one practical question after they open the page: what did they expect to find, and did they find it?