There are many types of "balance" in a photograph; for example, a mix of close and distant objects, a mix of light and dark, etc. Poor balance is not usually good, for example, a photo with too much light and no contrast. Experiment and learn how to provide a pleasing balance.
The photo below has an obvious theme in the balanced stones, but it also contains a balance of light/dark tones, foreground/background, sharp/soft areas, etc.
The next photo has a balance of light/shadow as well as technology/nature.
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