@Lucius
I think alternate history has ist appeal, but is also a very tricky terrain, depending on what you intend to do.
For fantasy and Sci-Fi you need good worldbuilding as foundation. The longer and more in depht the story is, the more worldbuilding.
With historical pieces you need to know history. The more realistic you want it to be, the better your knowledge has to be.
For both there is a lot of wriggle room, but thats the baseline.
For good (realistic) alternate history you need to know history, and you need worldbuilding. But you don't have things like magic or sci-fi tech.
And even with those things you have to extrapolate what would happen in the real world after the point where both timelines diverge.
Two examples:
Someone I know once read a novel and was gushing over how in depth it was, how detailed and realistic. Even believing this could happen in the real world under the right circumstances.
It was something about a war between US and China
Another guy, much more intelligent, slight obsession with chinese history and china in general, and a degree in political science denounced it as trash and told me barely anything in there would even work in the real world, and even if: Only if the entire chinese government was made up of complete morons.
Another one: Years ago I read a short story about Nazi occultists summoning succubi to our world. I was inspired to make a picture out of it. When I posted it on HF I added a little backstory. At the time I had read and watched stuff about the Battle of Kursk. And even in this setting where nazi germany summoned succubi and possible other demons from hell, and used black magic and occult science to create super-soldiers and weapons I was thinking: Would this relatively small operation I envisoned be able to win the Battle of Kursk? And if yes: Would Army Group Center be able to make another push for Moscow? Or Amry Group South for the Kaukasus? And it was just four lines for the description of the pic.
In the end I wrote that they used their demonic forces to win Stalingrad instead.
Oh, and there was a wild 22 November 1963 story where on top of the Dallas assassination everyone in the line of succession, ahem, joined JFK due to a variety of unnatural or natural causes -- everyone preceding RFK, that is. 
Maybe we need a "Leave your comfort zone!"-contest where each participating author gets assigned to write a type of story they usually would never write by the community. 
