The story I'm writing takes a lot of influences, and characters from mythology, including various gods. The problem I'm running into is that I can't figure a way to have basically normal characters be the protagonists (they have powers, but nowhere near to the extent of some of the gods) when they come face to face with threats that are potentially universal. They get stronger as the story goes on, but I really don't the story to become like DBZ, where the power levels get so high it makes no sense anymore. If anyone has any ideas on how to manage this, I would appreciate it.
Let them get beaten. Let them make dumb mistakes and get outfoxed, if they're not overpowered. Take their powers away, if you can -- give them restrictions and limitations.
Mythological gods were much more limited in their powers, and restrained in the use of those powers, than the modern version of Yahveh. They also had rules of conduct, more or less strictly enforced by the pantheon, and areas of influence that they could not expand without stepping on another god's toes. If mortals are up against gods in any kind of conflict, the mortals' best bet is to appeal to the rules divine conduct, or to enlist a divine patron on their side.
Set some hard limits on what their powers can and can't do. Introducing a cost and requirements system to their powers would help, too.
Depending on the circumstances of the pantheon they are from and their place in it they might not be all that powerful. Are they still worshipped for instance? In most such fantasy settings with gods, this makes a tremendous difference. Taking away the number of their worshippers or their temples puts a hurting on gods in most stories. Also as someone else mentioned many of the old gods had definite taboos about what they could and couldn't do and what their area of influence was. Between those two things, you should be able to reign little gods in, in most circumstances.
As other have said, depending on the pantheon, the gods were often a lot like mortals. They could die, be bound, defeated, etc. Gods aren't necessarily all powerful and you can use that to your advantage in the story. What pantheon are you choosing from or are you doing a mixture?
As of now, I have seven different pantheons, each occupying a different part of the world. The ones that I'm most trying to figure out how to incorporate are the Hindu gods (anyone who knows Hindu mythology knows how broken some of their powers are).
