I am writing a steampunk novel. One complaint about steampunk is that it is racist: it is solely about whites. This was a valid complaint. Then I read about the Zulu king Cetshwayo's trip to London in 1882. He was received with some respect and even got to meet Queen Victoria. This, I thought, was the perfect base for a steampunk story. So I introduced a fictional ambassador from a fictional African kingdom.
But steampunk is more than an 'alternative universe' story. It needs a touch of the supernatural. My answer was to introduce deities for rivers and hills. The Thames at that time was heavily polluted. Its deity was suffering. So I invented a campaign by the ambassador to heal the Thames. I have reached 60,000 words so I still have a long way to go.