Write a testimonial on someone’s product and have it posted on their site.
November 29, 2016
Order a sponsored post from a prominent blogger.
November 29, 2016

Ask someone to review your product.

Sites with active user bases can give you links with your keywords that can help your search engine rankings, in addition to bringing you direct traffic and a good reputation via favorable reviews. Search for relevant blogs and reach their authors.
Tip: Do not go after A-list bloggers, focus on the mid-list bloggers instead. These people are often much more accessible, and much more willing to check out your offerings.