You absolutely must be very detail oriented. You need to know about keyword density and be mindful of it when writing the content. You also need to be meticulous (don't know if that is spelled right) in your editing of the content you create. You cannot have bad grammar or mis-spelled words or it will cheapen the quality of your work, even if what you are saying in the content is top dollar stuff. You probably want to start with ezinearticles.com. They are probably the top article site on the net. Keep writing as much as you can for them, and you will get your content in front of webmasters. Include a link back to your site where they can purchase your content creation services. You may also want to consider posting jobs on elance.com and similar sites like that.
I'm starting to feel like her personal rep, but I always recommend Jenn's blog, http://allfreelancewriting.com. It's an excellent source for all freelance writers, from beginners to pros, and in all areas. She frequents DP as well, you may have noticed her around.
If you're up for a bit more advice, check out this free report I distribute through my site. Thanks! Rebecca
There are a few things you need... First off, a good grasp of the English language will help to get you started in the right direction. From there, market your services day in and day out. Finally, do not be afraid to start at the bottom. Once you build up a cilent list, you can then move up the food chain. Also, if we are throwing out resources, check out my blog at www.chrisblogging.com. I talk about content writing, copywriting, and how much you can earn.