Well I'm getting tired, but I want to throw a few more hats in the ring before I go. Regarding the accompanying photos:

I think with the leaves, the red is bright, the yellow subdued - but it is the subdued yellows that catch the eye in this instance. At the same time though, they enhance the interest of the maples.

The weight of the grasshopper is clearly balanced by the small stems on which it is perched (although they number rather more than "a few"). Although there is not a lot of colour variation, the insect is isolated and appears large, and so commands attention on those grounds too. And it has all kinds of texture.

The isolation of the yellow flower is undeniable, and so is the isolation of the insect on the petal. That flower would have been dramatically dominant even if I had not cropped the flower so tightly (to give the insect some presence). But the insect is a "dark element", of a different colour, and although small, it feels heavier than its lighter surroundings. Here we have isolation within isolation too.

The dark thorn tree balances the lighter cheetah cub. The cub, although it stands out due to colour and brightness, is locally balanced by the texture of the grasses of its habitat.

With respect to orientation, the contraposed diagonals of the artwork display do it for me. I think the lady on the left balances off the white umbrella on the other side too.

So yes, balance can be achieved in these various ways and with a wide variety of subjects. But you don't want so much balance that you suppress your subject. It should be noted too that the different principles of balance may sometimes be in conflict. And then I don't think anyone has raised the question of which circumstances benefit from balance and which might be better served by imbalance - can these principles be deliberately violated to create tension and when might that be desirable? Or is "balance" in some degree to be mandated in all circumstances?

So those are my excuses to display the photos below ;-))