A book of my own

Any suggestions for a person who is about to write their own book? Theme will be sci-fi, because I feel that every other theme has been covered by another writer already.

Won't be anything like things that already exist like Star Wars. I'm planning on writing something completely new, something that people will find interesting to read.

I've never written a book before though. Are there things that I should look out for? Applications that help out in writing a book, or should I just bring out the good old Microsoft Word?

"Sci-fi" isn't a theme, bro. And keep in mind that "other themes" are a big part of any science fiction novel. You're not going to go mass-market without mass-market appeal. You've got to write both a mind-blowing vision and a real human drama, hopefully consequent on one another.

You'd better consider starting with short stories too, if you're a new writer. Books don't just happen. Better to hone your craft for a while so you don't end up with a long manuscript whose quality of writing changes drastically throughout its length.

And like these guys said, you'd better learn your current science fiction better. Have you read your Charlie Stross, your Neal Stephenson, your Peter Watts, your David Marusek, your Paul Melko, maybe some guys like Eric Flint, Alan Dean Foster, Tobias Buckell, and plenty of classics (Cordwainer Smith, Niven, Heinlein, Asimov, Cherryh, Clarke, and so on)? I mean, if Star Wars is your best example of science fiction, you're probably not especially familiar with the genre. Your final product may not depend on your familiarity with science fiction, but some more experience will certainly inform the process.

Also, how about people post the best new science fiction authors, for OPs benefit and for the benefit of others in this thread?