It's difficult to really say without having more information.
Are you a new site in comparison to your competitors?
Are you optimizing your articles, i.e, including relevant and searchable keywords?
Are you giving lots of value and are your articles unique?
Are you using social media sites such as Twitter and FB to create relationships and network?
Look at some of these scenarios and see if you may improve on some of them if need be.
I do agree with the commenter above, guest blogging is a great way to showcase your best work and get your brand out there. It's going to take a bit of work though. I would suggest commenting regularly on a blog relevant to your industry, creating a relationship with the blog owner and eventually proposing the idea to them.