Do you really have to step on everyone else to succeed? The great news is that you don't. No one has to fall into the trap of "scarcity" vs. "abundance" as there is plenty of business and opportunity to go around.
In the freelance writing world the worst thing you can do is view everything as scarce, because it impacts how you interact with peers, how willing you are to partner with other creative folks and your writing craft itself.
In covering the Internet for over a decade as a freelance journalist I've marveled at how many opportunities are lost simply because folks are unwilling to move out of their comfort zone and open themselves up to new opportunities.
As a writer I've always lived by "pitching and swerving" to the next assignment and underlying that pitching and swerving is my full confidence that there will always be more assignments than I can tackle and interestingly there always is.
Take a good hard look at who you've been writing for and what the payoff is beyond the dollar amount. If it's keeping you from fully expressing your talents, then find other opportunities.
Here's a real world example:
Yesterday I just landed as a new PR client, a very well-known musician and am completely reinvigorated to tackle the PR side in the same way I would for a company, author or product. In many ways, the process is the same - getting the media the story, making your spokesperson available, being responsive and respectful to bloggers plus I get a free t-shirt and CD. (Cool!)
Make a commitment to write "outside the box" and you'll be surprised at the abundance that will follow.