I mentioned Digital Photography School as an excellent resource for tutorials. They recently celebrated their 8th anniversary and posted their 15 most popular tutorials.
Three of these are some great tutorials about ISO, shutter speed, and aperture, which are the three settings that determine how sensitive the camera is to light (ISO), how long your shutter is open to allow light in (shutter speed), and how big an opening you have for that light to come in through (aperture, which affects how much of your photo is in focus). I encourage you to check them out:
ISO settings in digital photography
Introduction to Shutter Speed in Digital Photography
Introduction to Aperture in Digital Photography
Then let me know what you think in the comments!