[mantone]

I would echo Del's point on Aperture Priority. I shot this way for many years  (and still do at times) and felt it gave me good control over an image, while still being somewhat autonomous.  It's a good starting ground on getting out of fully auto.

The way shutter speed, ISO and Aperture interact is known as the "Exposure triangle" and I would suggest looking that up on YouTube as a good starting point, there are some very good, easy to follow tutorials on there.