The most straightforward way to invent is not to somehow come up with something completely new, but instead to put together two things that exist.
Innovation happens at the intersection of existing ideas
Craft → Product Sense
People think invention takes all this time, but you only need two hours once a month. The thing is, once you have one good idea, it often takes years to express that.
You don't need very many good ideas to be seen as tremendously inventive.
To invent systematically, first you do need to be somewhat of an expert in whatever area you want to invent. But then the second thing people don't do is they don't spend dedicated time actually thinking.