There are two steps to getting work through
Learn to Determine the Quality of the Freelance Writing Job Advertised
Reading the descriptions carefully will reveal clues about the hiring entity. Is it a company or an individual? Many writers prefer to work for companies, but I don't rule out individuals altogether. I will work for individuals who have posted a pay rate that is acceptable, or otherwise indicated a market-appropriate pay rate is likely. I simply don't have time to apply for jobs for individuals who don't indicate one way or another, as, unfortunately, this rate is generally low.
Another clue is the method of posting. Jobs that post via Craigslist can be low-paying. Of course, if the job post leads to a well-known publisher or book packager-- apply, apply, apply! Most of the postings are in-between, though. These are generally medium-sized companies or publications that are not universally known. Read these postings deeper for clues. Is pay mentioned? That's always a bonus. If not, consider the hiring contact. Is it a person with a title, such as HR manager or similar? This tells you the company is large enough to have compartmentalized its processes into departments- generally reflecting the possibility of higher pay and a quality working relationship. Is the position very well-described? This might indicate a company with established job descriptions and processes--another good sign.
Lastly, I always look for postings that are specifically in my niche, or at least related to it. For example, I will always apply for writing work that focuses on Latino issues, but I might also open that up to publications that focus on other minorities, or other minority issues. This is to say that I AIM well.
Like many writers, I guard my hours. You should, too. Go into job boards with the conviction that you're going to pass up 95% of the jobs posted. This helps you to focus on your best opportunities.
Carefully and Purposefully Apply to Freelance Writing Jobs
First and foremost, apply quickly. I've seen some arguments against this step. It's true that you won't impress an employer by sending a resume within two minutes of a job posting-- did you really have time to consider their needs? But I generally won't bother to apply for a position if it's been posted publicly for more than a day or two (with few exceptions). Let me tell you why.
I posted a position on a smallish writing forum. On the first day, the replies started coming in regularly. I read applications and deleted those that were not qualified. I kept some of the best in my active inbox folder. By the second day, the response started to get heavier, and I found myself clicking on the applications with the most interesting subject lines. I figured I'd get to the others later. By the third day my in box was so inundated that I knew there was no time for me to read each application. By the fourth day, I was missing emails from clients or friends, as they were just buried. I simply had to get my inbox under control. My total applications for a lowish paying proofreading job? 121!!
Now, I am just one person, and I am in no way saying that this is the rule. In fact, companies and publishers have dedicated people or departments to handle this inundation. In my experience, timing is less important for these types of jobs/positions.
More important than timing, though, is proactively and purposefully applying to freelance writing jobs. Treat every job application like a full time job application. When people apply to full time jobs, they tailor their resume, samples and cover letter. I do the exact same thing for almost every freelance writing job. Yes, this will take more time in the beginning, but you will eventually produce cover letters and your
I'm sure much of this information has been heard before. The "secret" is putting it into regular practice, finding high-quality clients, and then pleasing those clients so that they always turn to you.

