For example, the main character has a "magic" sword. He'll find out over the course of the story that it's a piece of lost tech.
For mine, I write it like it's standard sci-fi, but with a few elements (like the sword) that look like magic. I already know it works, so I'm sticking to those limitations.
In a fantasy story with tech, I think you'd almost want to do the opposite, fill the world with wonder, and have a few items, that, while powerful, feel somewhat out of place. (I like to imagine what a Roman or medieval warrior would make of a man with a full-auto gun. )
- Aaron DeMott, writer of sc-fi and fantasy - http://aarondemott.blogspot.com