This may have already been said but co-partnerships with other websites in your niche.
e.i. - If you are in the dating niche and have a cool product you created then find related \ hubs in your niche and offer to send them a copy of your new product to review. Make sure to include a press kit which includes photos, a good write up on the product, etc. Do all the work for them so they have some unique and compelling content to publish. This works because for starters, they are referring you pre qualified traffic to your site for free and everyone wants fresh content. The trick is you must target sites that have decent traffic or your exposure will be minimal. An extra benefit is you will be gaining an authorative link that will boost your SERPS as well.