Here are a couple of thoughts:
1. You already have some unprinted shirt designs created, so it might be a good idea to shop those around to other contest sites- I've heard of several people who got freelance gigs after their work was seen on Threadless, TeeFury, DBH, etc, and plus linking your portfolio on those sites should lead to some traffic. If your design prints, you'll get even more.
2. Create a links page and populate it with the sites of your artist friends or artists you like. Then let them know you've done it- some will do the same for you, increasing your visibility and strengthening your connections.
3. If you want to be featured by, say, illustration blogs, start following them. Post comments often- your site is linked with your name, and you'll get some hits. Even better, if you know what you're talking about, you'll probably also get some credibility and build a reputation.
I'd also suggest making a list of online artists whose careers/gigs you respect. Some of the people on that list will be established, others will be more up-and-coming. Look at where they have their work linked and featured, because at least some of those places will also be an option for you.