Hiding or showing upcoming functionalities

We are developing a data-heavy site and I was wondering, how should we present (or hide) upcoming functionalities. Let's say in a form an option which will only be available later. Or a button that says 'create new xy'. What would be the best practice here? Should we completely hide the functionality until it is released, or show it, but how, in order to not end up frustrating the user by clicking something that is not yet available?

Would appreciate some help as we are not sure how to proceed.