There are lots of ways to go about attracting links which are not spammy. You may need to step out of your comfort zone a bit, though.
Are your potential readers on any social media sites like Facebook, Twitter, LinkedIn, Google+? You'll want to get active there, where ever they are. But make sure that the majority of your posts are NOT promoting your own stuff or you could get labeled as a spammer. One ratio I've heard tossed around is that perhaps one in every 10 posts should be promoting your own stuff.
Are there blogs covering your industry out there? Do you have a blog? (You mention article writers, so I'm assuming a blog or an article section on your site.) Find a couple of bloggers whose sites seem to get some fair traffic and whose writing style you like, then write them and invite them to guest post on your site. If they agree, you'll get some good content for free, and they'll almost certainly link to your site from their own in order to promote the article they wrote for you. And maybe one or more of them will invite you to trade guest posts, which would allow you to place another link to your own site on theirs.
Sometimes all you have to do is write a response to one of their blog articles on your own blog, including a link to them so your readers can see the original story. They may be inspired to write their own response to your response, which would probably include a link back to you.
If there are any publications in your industry that have online editions, you can do the same thing with them. Pitch a story idea, then when its accepted have one of your writers complete the story. In your bio accompanying the article, you can usually include a link back to your site.
If there are any professional associations or industry groups related to the topic of your site, join them, especially if they have an online member directory. That could be another inbound link to your site.
If you do something newsworthy or you can think of a way to relate what you do to some significant current event, a press release might be in order. The release on its own might not do all that much good, but if it's well written, newsworthy and topical, it might get picked up and republished on other websites. And those links may well do you some good.
You may not need an SEO firm as much as you need a PR firm, actually.
Edited by torka, 15 January 2013 - 12:15 PM.
thought of something additional!