Improving abysmal comprehension

I have very bad reading and listening comprehension. I believe the problem is not a lack of concentration, but a lack of knowing what to concentrate on. When listening I hear words, when reading I read words. I can listen to something I’m really interested in and enjoy it, but if someone asks me what it was about I won’t be able to say much if anything at all. Concentrating on just hearing words is obviously useless. I could try to visualize the words, but that doesn’t seem useful either. That’s just random senseless images.
I came up with the idea that I could try to make some kind of graph/mind map in my head while listening/reading. This would be used even for simple stuff like small talk. Before I begin training this, which would probably take very long, do you have another idea? It seems hard and exhausting to do this fast and for a long time, while listening or reading, so I’d rather not waste all my time on this if it’s actually a very stupid idea.