The most valuable thing I’ve learned in my photography class so far: the difference between the camera’s different metering settings. The default is matrix (or “multi-zone” or “evaluative”) which samples multiple places in the frame to determine the exposure. For my outfit photos, center-weighted might be a better metering option because the exposure is set to what I’m wearing, not the wall behind me (as long as I fill the center of the frame).
Now I’ve just got to remember to reset the white balance when I photograph indoors to offset the yellowish indoor lighting. I correct what I can in Photoshop, but the overall result is still a little too warm.