My story is set in a steampunk world, in the 1800s. Of course, to the characters the fact they have cars and airships is completley normal to them, but how to I make it clear to the reader that I've not just got a bad view of history (Giving Victorian's Laser Guns, ect)?
A: The cover art: Steampunk is fairly widely known, and the picture showing a female wearing a corset wielding what looks like a laser pistol made of wood will probably guess your modifying history B: Whatever politics and history you keep, your readers will know its fiction in the end. I really don't think you have a problem here, even if you mentioned the timeline of this novel and start mentioning all the high level steampunk era technology.
Yeah, I doubt anyone would think you're stupid enough to assume that cars and airships were around in the 1800s. Trust the readers!
And to alienate about a third of the people who like steampunk. But, yeah, steampunk is a pretty well known subgenre of alternate history/science fiction. We'll understand the idea once you throw around some difference engines or whatever it is you're looking to include.
Just write it as steampunk? It's a fairly established genre. Would you worry about making clear to the author that a sci-fi story is set in the future, so they don't just think you've gone mad?
Heh, I know. Went to a steampunky pirate wedding last summer and there were a lot of goggles and random useless cogs on things. I know there's more to steampunk than that, but it's what sticks in the mind...
Refer to some well-known historical event, but refer to it differently. For example, a novel might refer to the failure of the American Colonies to break away from England in the 18th Century. It need not be an event which caused the different timeline to form, just something significantly different from well known facts.