In my opinion, one of the hardest parts of product and general management is drawing insight from the right sources to determine ‘product health’ to identify where to focus, especially when managing multiple product lines.
In my experience I try pull data from three independent, uncorrelated sources to inform where I should focus my effort - the data, the team, and the users:
Data: Design dashboards that give you the metrics at the right level of detail on a daily/weekly/monthly/quarterly basis. Be able to translate data into concrete hypotheses and insights.
Team: The general manager (GM) or product lead of the business is your main source of information, but make sure to spend time with team members and other functional leads as well, so you can validate/invalidate what you hear from the GM. The broader team is also an incredibly strong resource for ideas for new features.
Users & Customer Service (CS): It’s important to maintain empathy/understanding of your customers, even when you’re a step removed from the product.
On a regular cadence (e.g. weekly), spend time reading user reviews, blogs, forum posts etc.
Get quantitative and qualitative information from the CS team about what users are saying about your products over customer service channels, either through a short meeting, or a list of top 5-10 issues each week.
Spend time actually interacting with customers, and responding to them (directly or on forums for example).