Welcome to Constant-Content, Warren. Nice to e-meet you as well.

I hope that your experience here with C-C will be as pleasant as mine has been so far. I've only been on this site for a month and I've gotta tell you, it's been an eye-opening experience. It is beyond cool to get paid to write articles. These forums are full of helpful people who are ready to offer useful advice despite the fact that they may be competing against you for the same work. It's really a very unique place, and I love it so far. I'm betting that you will as well.
I like the "I'm just going to forge ahead" attitude. That's going to help you out a lot in the long-run. I think it's fairly normal to have jittery nerves when first starting to write for this site. After all, the editing process can be fairly harrowing, and after a rejection or two you start to question your abilities as a writer. Then, once you have the editing process down, you begin to question if you're ever going to sell anything. That's where the forums come in handy. Make sure you read about other people's experiences when you're getting down in the dumps. Sometimes it takes some time for your profile to gain momentum, and the timing of sales doesn't always make sense, but if you stick with it, you'll begin to see rewards for the time you've spent here. I'm going to get off of my soap box now...people are probably tired of hearing me preach the benefits of using C-C.
Regarding whether you should write for public requests or not...I'd recommend both writing for them as well as putting together articles that draw upon your own personal experience. Oftentimes, writing for public requests requires you to spend time researching the topic before writing for the request, and this cuts into your money made/hour. It can be a great way to get a regular client though. Read through some of the forums to learn about the varying degrees of success that people have had with the public requests.
Well, welcome to C-C. I wish you good luck.
Mike