Carroll O'Connor

Write as precisely and as lucidly and as richly as you can about what you find truly mysterious and irreducible about human experience, and not obscurely about what will prove to be received opinion or cliche once the reader figures out your stylistic conceit. There's all the difference in the world between mystery and mystification.

The historical novelist has to consider what has actually happened, while the SF writer is dealing in possibilities, but they are both in the business of imagining a world unlike our own and yet connected to it.