When I started I took other jobs to help pay the bills, but I never stopped writing. Now I'm at the stage where I can afford to say 'no' to a project if I don't fancy doing it. This has helped me to build a reputation in the industry as a solid, professional writer. Don't try to be commercial just to sell your work - write what you want to write, not what you think a producer or publisher will want to buy. There's no point jumping on a bandwagon - it will have rolled off into the distance by the time your work is produced.
Strong characters are the most important aspect of writing.
If you come up with some colourful characters, understand who they are why they do things, you'll find it much easier to write a story. Once those characters were developed, the story was easy to write. Up until now it's been hard to contact agents and publishers, especially for new writers. In fact, many agents used to go out of their way to avoid their own clients, let alone prospective ones. Now you can reach these people with a simple e-mail, and it's becoming much easier to submit work.