One small change can make a BIG difference to your Product Owner success. Before worrying about putting value on backlog items, here's some simple tips.
With the Agility mindset, it's critical to understand the concept of "being" Agile. Some people want "to do Agile", but you don't DO Agile, you must BE Agile.
Good software solves the customer's problems, but to provide the right solution, you must start with the right problem.
Analysis, design, coding, and testing are done constantly rather than in phases, meaning testing ISN'T just a phase but an ongoing part of Agile Development.
Scrum Sprints provide empiricism, part of the Agile core beliefs, which is why extending a Sprint is never a good idea!
The fastest team productivity killer is working on 3+ backlog items at once. You'll end up with a team that's great at starting work, but lousy at finishing it.
Plan your transition to Agile Development for the long haul. It's more than just code. Treat it that way!