BS & MS in CS. Worked at one of the big 4 (google/apple/amazon/facebook). Got my MBA from a top 10. Currently in venture capital. If you want to stay in engineering, there's no need for an MBA. It only helps if you want to pivot.
-Background in software engineering and human-centered design. The best product managers I've been around have a mix of technical, business, and design talent, with the strong PMs excelling in at least two of the categories.
-Understand the difference between good and bad products. Actively examine products you use on a daily basis, both physical and digital. E.g. why is my shower setting designed this way? why did I push on a door that needed to be pulled? To flex this muscle, read "The Design of Everyday Things" by Don Norman and check out Tony Fadell's tech talk on product design.
-Be a people person. You need to be able to communicate product ideas clearly to everyone from marketing to HR to engineering (obviously).
-Be entrepreneurial. You're the "CEO" of the product, so you need to know the product/service inside out. Everything from the software stack down to the marketing materials to the help center articles should have been on your radar at some point in the release cycle.
-Protect the engineers. Don't let management demand too much and be vested in their success.