There are billions of gods in the worlds. They swarm as thick as herring roe. Most of them are too small to see and never get worshipped, at least by anything bigger than a bacteria, who never say their prayers and don't demand much in the way of miracles.
They are the small gods - the spirits of places where two ant trails cross, the gods of microclimates down between grass roots. And most of them stay that way. Because what they lack is
belief
A handful, though, go on to greater things. Anything may trigger it. a shepherd, looking for a lost lamb, finds it among the briars and takes a minute or two to build a small cairn of stones in general thanks to whatever spirits might be around the place. Or a peculiarly shaped tree becomes associated with a cure for disease. Or someone carves a spiral on an isolated stone. Because what gods need is belief, and what humans want is gods.
Often it stops there. But sometimes it goes further. More rocks are added, more stones are raised, a temple is built on the site where the tree once stood. The god grows in strength, the belief of its worshippers raising it upwards like a thousand tons of rocket fuel. For a very few, sky's the limit.
And, sometimes, not even that.