As to how I write?
Well, during the week I generally write after Roadbuster's gone to work (so he can't disturb me) and keep it up until I go to bed. I have to have music on in the background when I write. Sometimes I'll write a scene to a deliberate set of songs that I'll create a quick playlist out of, and others I'll just have some random mix going on while I work. Now there have been times where I skip through songs because while writing say a fight scene say Rick Ashby's "Never Gonna Give You Up" is going to completely break the mood.
Then again there was that one time where I wrote Saber/Archer porn and my Ipod was suddenly like, "Metalica is the most awesome band EVAH!" and then decided to play "Master of Puppets", "Ain't My Bitch", and "Fuel" while I was writing fluffy porn. Yet somehow it worked so I wasn't going to argue. I did stare at my Ipod in confusion though.
On the weekend if I write, I generally have tea at my side because I don't have to worry about going to bed to go to work the next day.
Now my style of writing is heavily influenced by Joss Whedon (even now I'll go back and watch episodes of Buffy and Angel to get inspiration when stuck on something) and, this may surprise people, a young adult romance novelist named L.J. Smith. I read all of this woman's books when I was growing up and starting to write. Her prose was crisp and easy to follow, she had a good handle on characters, and the romance never felt melodramatic like a lot of teenage romance novels do. Looking at you "Twilight"; seriously, if you want to see a good teenage girl vampire romance handled well, read "The Vampire Diaries" trilogy.
Then as I grew as a writer and read more stuff like Neil Gaiman and of late Clive Barker have really inspired me. Christopher Golden was an author I read a lot of. His Shadow's series was Urban Fantasy before it was even named as a genre. They're being reprinted, so you might want to go check them out.
I tend to a Third Person Limited style. I'll write in Third Person, but the perspective isn't some omnipotent narrator, but focused on what one individual is seeing and thinking. Then when I switch perspectives I'll do a scene break and then go on with the new character.
Now to why I write?
I write to stay sane, and yes, some day I would like to make a career out of it. That's part of the reason I haven't written a fanfic in ages- my original stuff is taking off. However, I will be the first one to attest this.
Writing fanfiction is great practice before you jump into something original.