What is your business model like? Without divulging your actual site (as that's against our rules), are you an online publication that makes money from advertising ... or an eCommerce site that sells a product? Or are you an online service? Do you charge by subscriptions or a one-time fee?
Companies with different business models have the best results advertising in different ways. AdWords tends to be best for eCommerce sites when you use their conversion tracking ... You know exactly how much money you're making off of each visitor and you know exactly how much money you're spending off of each visitor.
Publications that earn revenue from advertising are a bit different ... The money is made more in word of mouth marketing and ensuring really good SEO, because that ensures free traffic from the search engines over an extended period of time, but requires a constant supply of new content being posted daily.