Order a sponsored post from a prominent blogger.
November 29, 2016
Ask tech-bloggers to use your software and review it.
November 29, 2016

Find beta-testers on special forums and sites to test your software.

Register on beta-testing forums and ask people to test your software. This way you will get valuable advice on usability, one-way links from the forum, and some forum users can write about your software on their sites.
Tip: If you need a link for ranking, not only traffic, check whether the “nofollow” attribute is used on any given forum.
Some of the places to start with are: