There is the first time for everything. Someone had to cook the first animal. Some one had to eat the first artichoke. Someone had to invent the first spear, light the first piece of coal, melt the first metal, build the first house. Tell a story of discovery. What would it be like to be a cave person discovering fire can be tamed?
Science fiction is entirely based upon extrapolation and what ifs. Take some human need and invent a technology to fill it. How would the technology effect change? Try reaching back into the past. Eliminate a technology. What if radio and television were never invented? Bring present technologies into the past. How would the cellular telephone have changed history? Tell some historical and sociological stories. What if the United States was founded by Karl Marx instead of the founding fathers?