When solving problems, it helps if you are analytical. As in:
A f;lash photo is, at least in principle, always a combination of an ambient light photo (unless you are in a coal mine a kilometre underground), and a flash photo. They are both affected by aperture and ISO, and the ambient photo is affected by shutter speed also, while the flash photo is affected by flash power also.
Simple, but extremely powerful. With this knowledge, you can start by perfecting the ambient photo, then add the flash photo: and it works every time.
Now preparing for my evening Sheridan College class. Can you tell?