The photos you are showing in this thread started out out-of-focus. At a size less than a postage stamp - it isn't so obvious. At a size that is 20-times life size - its going to look bad when it starts life OOF.
How are you setting focus before you take the photo? Spot focus? Zone? Auto-focus?
If the latter - the camera will often struggle to find a focal point - usually by looking at high contrast zones. On your photo on the clear glass frog - it found that focal point behind and left of the marble on the circular edge of a hole, which you can see is fairly crisply focused.
In another photo it seemed to struggle to find a focal point and settled (and not too well) on the background cloth behind the marble (wavy weave had the contrast).
Good focus starts with good lighting and understanding how your camera focuses, and your options in that camera for selecting focal points. If your camera is "hunting" for a focus - thats a hint that you need to either change modes, get clutter out of the frame or adjust lighting.
The EXIF information is stripped from your photos so I can't see which camera you are using.
Its become popular to post photos that are 20-times (or more) larger than the marble. That has caused a lot of folks to sacrifice focus for size. They achieve that by bringing the lens closer to the marble than the focal range. Result: poor, blurry focus. I'm not saying that is the cause of your problem, but I see it a lot. Don't get closer than your camera can sharply focus. Also - optical zoom is far better than digital zoom. The latter introduces compression artifacts.