A former colleague of mine once made the statement "The bag is full of good ideas". I agree. I've never found there to be a shortage of people giving opinions about new features or new product ideas. I have my own massive list of product ideas too. My team has backlogs that are a mile long.
Most of this we will NEVER build.
All teams have limited resources and time. These are far more scarce than ideas. And often, most "good ideas" are probably not that good of an idea anyways. As I said before, execution is key.
So how do you choose what the most important ideas are in your bag? Which ones do you want to spend your precious resources on?
You need to understand your business well enough to really know what financially is going to get you furthest. You'll need to balance short term tactical need and the strategic wins. Keep it simple. For me, the key is listening. Listening to everyone. But it isn't executing exactly what they are saying, it is know their motivations and the hurt behind what they are saying. If someone is saying "I really need a new button over here that does XYZ", it isn't about adding a button. It is about understanding that they think they need a button because they are forced to do some menial task over and over again and they want to make that task quicker. Maybe you should find a way to remove the task all together. Your job as a product manager is to see past "the button" and remove the hurt.
You choose ideas based on listening, knowing what is going to get you furthest most efficiently, and keeping it simple.
You notice I didn't mention doing a lengthy ROI analysis or official market studies. You should know your business well enough to not have to rely on these lengthy tools. But you should be out there talking to your customers and listening.
Listen, see past "the button", and go ahead....reach into that bag.