The most important thing when writing is ... well, writing! But, you should also start to consider other factors that will be pivotal in determining success and fame (well getting your name out there at least).
If you intend on epublishing (even if you're not) I would like to suggest a very useful read from smashwords. It's the 'Smashwords Book Marketing Guide'.
This FREE read will provide you with priceless insights about the competitive world of novels. It details the most effective 'tricks' for promoting your masterpiece on the web, from creating book trailers, to starting your own blog (who would have thought!!!). Enjoy.