To be a professional content writer, it would be good to have your own website or blog and promote it. once you get established you can offer the content writing services to others. This is long but effective way of getting the online writing jobs.

On the other hand there are many websites which offer you to write and promote your write up on their platform and share the revenue with them such as; infobarral, hubpages etc.

Another options are odesk, elance, freelance, iwriter and so on. these websites allow you to bid for getting the works from the advertisers on their website, but I found it difficult as newbie.

The website I liked the most is "bubbblews" it is a revenue sharing website, which requires minimum 400 characters to write, it is very much popular among writers.

Hope the information will help!

Thanks.

You might look into iwriter.com and textbroker.com, I have not worked with them, at least one has a quality based pay scale that requires you to submit a number of base price articles before qualifying.

The freelance marketplaces like Elance and Odesk have orders for 10 packs, winning bids is harder than dealing with the brokers.

Odesk.com has about 420 different qualification tests which can help someone with no track record of completed projects to win job bids

https://www.odesk.com/tests

ddd

odesk, elance