Hi,
Flash photography is not difficult at all if you just want a " normal " shot. Set ISO to 800, f5.6, aperture priority, first curtain flash sync, TTL-BL on yr SB-XXX Speedlight, metering pattern set to matrix, and you WILL get most of yr shots of acceptable standard (except yr own composition).
But if u want shots that are more creative, natural looking, etc. then some fine adjustments may be needed.
For me, when shooting indoors w reasonable ambient light intensity, I first meter the indoor light in MANUAL mode. I set the aperture to f5.6. I set shutter speed to 1/60 sec. I then adjust the ISO manually until I get a properly exposed picture.
Then I set the Mode on my SB900 to TTL-BL (Thru The Lens Balanced Fill Flash). And because I want the flash to provide only fill light n not to overpower the ambient light, I set -0.7EV or -1.0EV on the Speedlight.
This setup has given me the HIGHEST percentage of good shots when working indoors n w flash.
Hope this helps. Fred