The importance of a Product Owner

Companies using regular Project Management methods and willing to start using the Scrum Framework usually take a lot of care when hiring the Scrum Master (SM). Of course they need to hire someone that has lots of experience managing teams and that "achieved to multiply" n times the velocity of his last team.

But not all of these companies understand that the key artifact of Scrum is the Product Backlog, and the responsible of this artifact is not the Scrum Master but the Product Owner (PO).

Having a good SM and a great development team with a bad PO is equivalent of having a hamster engine powered Mustang.

As explained on the book Enterprise-Scale Agile Software Development "In an organization with established agile skills and Scrum-based projects, with experienced developers and strong Scrum masters, a bad product owner can turn an effective team into a frustrated and ineffective mess."

The success of the sprint depend on several factors (good understanding of the stories and good complexity estimations among others), and most of them depends of the quality of the backlog stories, this means on the work done by the PO.

Basically, the success of a product depends on the PO. Here you can see some examples of bad PO practices in the post "How to create products that customers hate."

A good product owner should:

Understand the product

"If you can't explain it simply, you don't understand it well enough."

Albert Einstein

This seems to be a stupid and obvious suggestion, but I can assure you that all the product owners have tough times trying to write a set of stories to describe a feature of a product. And the only PO that achieve this are the ones that really, really.... really have a clear idea of the feature to be developed and the "why to be developed".

Typically, a bad story is the one that the developers do not understand or the one that can't be estimated in complexity points in a couple of minutes by the dev team.

Never underestimate the power of prioritizing

Being negligent with prioritising the stories while using scrum is like being negligent with the steering wheel while driving a car. The PO is the one that will trace the path for obtaining a product by giving priorities to the stories in the backlog. Giving life to the backlog is updating the priorities and adding or changing stories day after day. This is adapting the requirements depending on the context of the current market.One of the advantages of scrum is the flexibility of changing your mind at any time, and this is possible by mantaining your backlog alive.

Learn to write a good backlog story

You can have some good tips here

Be present as much as you can

Sometimes when the team starts to go technical, some of the product owners have the feeling that they are no longer needed. For example when starting to define the tasks of each story. Keep in mind that the team can have a doubt about the story at any moment, in general the team will go back and forth from technical to usege requirements. And it's not the same to ask directly the PO during the meeting when the ideas are fresh, than seeing him later to solve doubts. Not having a strong presence of the PO can harm the team's velocity.

If you are interested on becoming an excelent PO, I suggest you the book  Agile Product Management with Scrum