There is nothing that will beat speaking to your potential customers directly to discover their needs. You may have a hypothesis of what you want based on your own needs, but you should conduct some research with users to validate.
If you already have customers, seeing how they use your product is key to understand the blockers, usage patterns, and hence new features that would provide increased value whilst remaining consistent with your overall offering.
Ideally, you do that F2F or via an actual discussion.
If not possible, or too difficult to manage, you can use tools like Hotjar to record your users interactions with your product. It is super insightful.
Last - you are the founder/creator. It is normal to have a roadmap in mind, with a set of features you believe will appear to your market (the contrary would be concering).
But you need to remain aware of the 'founder's bias', where as a founder you think everyone else thinks like you / has the same needs and pains. Hence testing your ideas against your market being key.