My view is that the two most important things when taking the usual still photos are:
- Optimum exposure
- Sharp focus.
As a beginner, maybe try the following:
1. Optimum exposure:
Per Google, the Z6iii only allows zebras in movie mode but not is still mode. That is a real bummer. However, it does allow the histogram overlay in the viewfinder (VF). If that's true, try the following:
..... a. Set the camera to P mode.
..... b. Enable the histogram overlay in the VF.
..... c. Frame the scene in the VF. Adjust exposure compensation so that the bottom right edge of the histogram mountains just touches the right side of the histogram display. (known as the ETTR method of setting exposure) This will give you the optimum exposures without blowing out the highlights.
..... d. Only do steps a and b once. Repeat step-c for every shot. This should result in optimum exposure for almost every shot.
2. Sharp focus:
..... a. Do not use auto focus.
..... b. Set the camera to use center point focus.
..... c. Set the focus square on the subject and half press the shutter button to lock focus. Recompose for the scene you want. Press the shutter so slowly that it surprises you when it trips. That should give your sharp focus on the subject you want.
Experiment with aperture and shutter priority modes as the situations require.
Hope this helps.