Using the previous tips, you've written an exciting, unique job description for your open engineering position. After you've posted your job to your company website, along with your large job boards of choice, what more can you do?
There are many online communities which run tech-focused job boards; these will put your job description in front of the right audience.
Make a note
Look for communities which provide resources for engineers, like Stack Overflow (careers.stackoverflow.com), professional organizations like the Society of Women Engineers (careers.swe.org), or tech news communities like TechCrunch (crunchboard.com).
Make sure you get a feel for the individual community before posting; smaller communities might respond better to a more casual writing style, for instance.
With persistence and careful targeting of your job advertisements, you will quickly see a benefit in the quantity and quality of applicants your job descriptions draw in.