When I first handled a digital camera, I did not know to surf the internet for information on camera operations, nor how to look for information on understanding the concepts and relations between shutter speed, aperture and ISO. The internet wasn't saturated with such information back then. It was 10 years and more long time ago.
Even when I got my first DSLR, making full use of the camera's setting was alien to me too. I had joined group outings to shoot photos of people but that wasn't fruitful in terms of learning photography for me either.Things changed when I started shooting for Dreamstime. Out in the streets shooting stills, I began to understand the function of the aperture priority mode and perfect it on a personal level. I learn not to always use the widest aperture as the options of shooting at the middle setting of the aperture range yields the sharpest images. When the light is lower I can always increase the ISO to the camera's usable range to brighten things up. It was not difficult for me when I get the hang of it. Everything is clockwork.
One other thing I learn is not to machine gun between shots. Visualize the image in your mind and compose it there. Move yourself to the spot for the best angle and take the shot. You only need one press of the shutter most of the time. Sometimes I take a few, when the subject is interesting and the situation allows me to move freely about the subject.