I've been working on a massive book of history for the world ive been designing now for about a year. Currently im at around 317 pages written and not a quarter of the way complete. But i have two questions for all those homebrew dungeon masters out there.

First, how do you deal with the gods of your world? I have four churches currently and many gods all based on different kinds of pantheon ideas and designs. And while gods are immortal and thus play their own game very slowly. I still see that gods would continue to move the pieces on the massive chess board to obtain more power for those who want it. So do you decide all your gods moves or do you let players use the gods and let them make plans? I have been toying with the idea of setting up a "god" campaign where i let a few players in to help me run the world overall and make decisions on what they would do at certain times in the five games im running. What do you all think of that?

My second question is, for the homebrew DM's out there, how do you design the histories of your races and world overall? I've been practically designing this entire world on my own. From the simple design of magic in the world to the whole 10,000+ years of history of each race. I plan to do the books in increments i.e working on the current age that my players are in. And when thats done, start the age before it and continue to work my way back to the founding. I do not plan to do language at this point or go to in depth with military tactics or anything of that sort currently. But its a monumental task and i can't decide if i should bring on extra people to help me write or if i should continue to try and just push through it. 

The way I deal with gods is usually some sort of belief system. Every intelligent creature has a certain amount of belief. This is split up between the different things the creature believes in, even the tiniest bit. A deity's power is determined by the amount of belief they have, so they constantly are manipulating mortals to gain more belief. This means that even things such as the tooth fairy or Santa Claus or the easter bunny exist, as well as countless small gods that exist solely because they exist as concepts in the minds of a few mortals.

     When I write the histories of my worlds, I follow a (general) formula. I build the outline of the races, cultures, and geography, fill in the details of the stuff that is most important to me, then play a few sessions. The players are a HUGE factor in the world in-game, and they help me to set the tone for the world they are playing in. I have two campaigns, one super light-hearted and fantastical and one grim-dark and realistic, but I didn't know which would be which until a player in the first named is kobold Gizzard the Lizard Wizard, which led to the kobolds of that world being uber Alice in Wonderland-esque. You can fill out thousands of years of history by puzzling through how the Aasimar player is the way she is. How was she created? Is that process common, or seldom seen? What is the potential relevance of aasimar in different cultures? 

I find things like those  to be great jumping off points.

Hope you find something helpful here!