In my case, when writing Sakura Blue and its sequels, I can't claim any experience using my body's bioelectric impulses to read people's memories or kill them in any number of agonizing ways. It's fun to imagine, sure, but it's not something I've ever done and it's not what the books are about.
To me, writing what you know comes down to two things: setting and emotion.
Setting is the milieu, the places and atmosphere that define the story. Is the setting bright? Cheerful? Dark? Big, with wide open spaces? Small, confined to a single house? Does everything happen in one town or across galaxies? The tales of the Buddha's Relics are set all over the world. The vast geography is critical to the flow of the story, taking readers to places they want to know but have never experienced.
Better still, the setting is seen through the characters' eyes. New York City is a far different place to Carrie Bradshaw than to Jack Reacher. How a character feels about a place influences how we, as readers, understand it.
And that brings me to my second point: emotion. No matter where they live or who they are, all of your readers are emotional people. Jean-Luc Picard and Fitzwilliam Darcy, however different their experiences and worldviews may be, resonate with us because we can relate to their emotions.
Giving characters emotional depth is the single most important job of a writer. If we can't emotionally relate to a character, we won't care about them. And if we don't care, we won't read the story, never mind shell out our hard-earned money for the privilege. Even bad guys - in some cases, like Darth Vader, especially bad guys - can be emotionally compelling. Who hasn't want to cast off the inhibitions of polite society, even if for a moment, and wreak havoc on an obnoxious boss, client, driver, or that idiot on the subway who keeps popping his gum?
Emotions build connections to the reader. However brilliant your descriptive powers when writing about a building, room, or landmark, your effort will be wasted if you don't build an emotional connection with the reader. Why does the Golden Gate Bridge or main character's childhood basement deserve such rich treatment in your story? Why should the reader care? The best way to do this - and, in my opinion, the only way - is to give your characters honest emotional reactions to the world you're building for them. If they react in ways that are true, the reader will accept it and share the reaction.
And that's the connection right there.
These two things, setting and emotion, are just the beginning of the story, not its end. Without them, though, your writing will be flat and interesting to no one. Flat is for pancakes. Your readers deserve the whole banquet.