Part of it is preference, and there's no accounting for taste...

But there are more concrete aspects as to what makes a photo good.

There are the technical aspects
-Proper exposure
-Properly focused subject
-Contrast isn't out of whack
.... etc

Its as much an art as a science. The rule of thumb I usually go by is that a good photo is interesting (which is where the person taking the picture comes in).

Even a boring everyday item like a toothbrush or pencil can be made interesting if the photo is framed/edited in a way that shows you a perspective you dont' normally see, or that is appealilng.

Similarly, you could wander into the enchanted forest and end up snapping photos of a Yeti riding a Unicorn that end up being bad because of bad choices with angles/lighting, etc.

If YOU like your photos, then keep at it. It is good to compare your pictures to other photos so that you can have a more informed context from which to judge your own work... but don't unnecessarily put stock in someone else's opinions about some pictures just because they have a bigger camera than you or have been taking photos for longer.

Even the most reknowned photographers take a lot of stinkers and boring shots.