If someone asks me what is the most difficult yet powerful thing to do, I'd say it is training my mind. I'm sure you might agree with me. Deciding to do something is a different thing but actually doing something is tough. But it is difficult only if our mind thinks so. If you have the will, you'll eventually find out the way. And to go through this way, you'll need to train your mind.
General knowledge is the information accumulated over time and years through different mediums like reading books and newspapers, watching television or listening attentively. It is not a detailed learning like a college degree but it will for sure give you more confidence and make you more aware of the world around you.