Oh, project managers, how often are we mixed up? We even share the shortcut - PM. When a few years ago many project managers jumped on the Agile bandwagon to become coaches, scrum masters and delivery managers - I thought it will help to solve the confusion. No luck, people still often use project and product manager terms interchangeably.
This is hardly surprising as product managers regularly need to put their project hats on and deliver. Unfortunately, it is much harder for project managers to break into product. The learning curve is steep but manageable if you organise yourself well. And isn't that what you do best?
Leverage your strengths
Good project managers have several skills highly valuable for the transition to a product role. First of all, project managers are masterful communicators. They can identify all stakeholders for a project and find the most effective ways to collaborate with them. This is a critical skill in any product role, sometimes two-thirds of what we do is communication.
Secondly, many project managers will have a good knowledge of the delivery process. Even if they're not technical they would have experience dealing with dev teams, marketing teams, sales and all others needed for successful product delivery and launch. Chances are high that project managers will find it easier to start their product careers in a delivery-focused role, such as a product owner.
What to learn
Quite a lot. First and foremostly - product discovery. Naturally, project managers are biased toward action, towards doing something. In the past that was their main job - execute the project excellently. As product managers, they will need to learn when to start doing something and when not to. They would need to learn quickly that doing should not be the default option in a product role.
Secondly, project managers will need to learn discovery techniques so they can effectively find market problems worth solving. They would need to work closely with designs to validate solutions and make sure only the best ideas are getting developed.
Lastly, project managers will need to learn about the financial aspects of products. A release is only one step in a product's lifecycle. Usually, it needs to grow, get optimised, monetised and eventually retired. All those things are the product manager's responsibilities.
How to test drive
Often project managers work closely with their partners in product. Therefore it should be possible for them to observe and ask questions. Collaborating on a project, they could inquire into the "why" behind, understand better the underlying problems that gave life to the project, how those were discovered and validated. If possible, it would be greatly beneficial for project folks to shadow a product manager in her discovery, especially during customer research and solution validation.
After the project is shipped it worth keeping an eye on it going forward. This way one can learn how successful it turns up and get insights into the post-release product lifecycle.
As in other cases, running your own little project as you'd do in a product role would help immensely.
Summary
Project and product management are two distinct and vastly different roles. Successful products are often built with the help of sequential projects and therefore product folks are expected to be able to project manage. This gives a headstart to people who want to switch from project to product management. And yet, to be successful in a new role, project managers need to learn a lot about how products are getting built. Most learnings will be in the discovery and post-release product lifecycle. Working hand in hand with their partners in product, project managers can get themselves up to speed fast and kickstart their product careers with a delivery-focused role, such as product owner. And it's only upwards from there, good luck.