One most important thing, you will always need as a freelance writer, is an impressive portfolio. A portfolio is a powerful tool to attract new writing work. When you are starting out as a freelance writer, you might not have a portfolio. When I started out, I did not have one because I just wrote papers in my school and college days but did not have a published work. In the beginning I took up two full time jobs as writer. There I was supposed to write test samples to get the jobs but still that did not made to my portfolio. Again, during the job I wrote thousands of articles but with no byline; I wrote as a ghost writer. If you are writing as a ghost writer, you are not creating portfolio of your work as, for getting portfolio, you need to have a byline attached with your writing. Let us see how you can create a portfolio.
Start a Blog
The first you can do for creating your original work is to start a blog of your own. (Though, I started a blog very late!) You can start a blog about any subject you like or about your own personal experience. Here you can have collection of your writings and you can give the link of your blog to the prospective buyer.
Writing for Article Directories
There are hundreds of article directories on the web. You can make use of them for creating an impressive portfolio for you. You just write articles about the topics you feel comfortable in and submit it to the article directories. They publish your articles with your byline. Though they do not pay for writing articles, but publishing your articles there creates credibility for your work. Believe me; it can do wonders to your writing career! Ezinearticles, Articlebase, Hubpages are some of the good article directories.
Writing for revenue sharing websites
When your sole aim is to create a portfolio, then use these websites as a platform to showcase your talent. You can submit your articles at websites like Associated Content, Bukisa.com and others to publish them with your byline. In addition to publishing your article, they pay you some revue on sharing basis.
Whenever you apply for a new writing job, some people ask for writing a new sample which they do not pay for. In that case, collect those samples and post them on your blog. It is good idea as writing for different people means writing for different subjects. A writing done by would never go waste.
While Ghost Writing
For me, even ghost writing helps you assemble a portfolio. How? When you write articles related to different topics, you gain valuable experience which is worth in gold. This is a worthy advice from my experience. You can send links of your published articles (ghost written) to your prospective clients. They can check your writing skills by that also. But be honest! It pays. In my case, it works. You too try it.
These are some of my experiences. If you have any thing to add or share, please feel free to comment. Your comments are very valuable for me.