The corollary to being reliable is to make sure you manage yourself.If you can manage all your tasks and deliverables without reminders, you will be treated like the golden child.
If your boss or colleagues never need to remind you about a project, deliverable, an answer to an email, etc., they will be able to take a load off their mind and be allowed to focus on other areas. And they will appreciate not having to have the uncomfortable conversation with you (“where is that item that was due yesterday?”).
This takes a lot of hard work and organization, but most people can do it. You don’t need a PhD (or even a college degree) to be on top of everything. You just need to be organized and prioritize its importance. Of course, while most people CAN do this, most people DON’T do this — so doing it will be a huge differentiator for you.