Anyone in hiring mode faces several challenges: A fiercely competitive market, Millennials who loathe to stay in the same job for long, and the fact that the people you actually want to hire may not be looking. That's according to former Googler Sarah Nahm, founder and CEO of Lever, a Silicon Valley-based applicant tracking startup boasting investors such Yahoo CEO Marissa Mayer, Box CEO Aaron Levie, as well as Yelp CEO Jeremy Stoppelman. Here are a handful of smart strategies and 13 modern tools she says you should consider if you want to surface the best talent.

1. Focus on niche online communities.

While traditional job boards like Monster and Indeed may still get traffic, Nahm says they create a lot of screening work for little reward. Even LinkedIn is getting crowded, with 94 percent of recruiters using the professional network to source candidates. Instead, niche portals are more direct ways to find talent. For example, check out AngelList for startup talent, GitHub and Stack Overflow to find engineers, and Dribbble and Coroflot, where designers hang out. Nahm's favorite: MeetUp, which you can use to access attendee lists for groups that meet around shared interests.  "[It] can be a fantastic, focused portal to identify talent for really specific jobs," she says.

2. Empower every employee to help with sourcing.

When you're going after the upper echelon of the workforce -- people who have a lot of choice and may not even be looking for something new -- you need to use your employees as recruiters. "Engineers are better at hiring engineers, sales people are better at hiring sales people," she says. "The domain experts in your company are going to be the best at identifying prospects with specialized skills, and they're the best [people] to start the conversation and... convince [someone] to accept an offer when the time comes." Here she suggests Lever, an applicant tracking system that includes tools for social sourcing. Lever's browser plugin lets anyone in your company click when he or she finds someone online who would be perfect for a position.

3. Emphasize diversity.

Nahm suggests Entelo, which offers an algorithmic sourcing platform that includes a diversity product to help a company surface under-represented groups. Alternately, WhiteTruffle takes a different tack. "They actually strip away all identifying features on a prospective candidate's profile in order to promote objective and anonymous matching, [to] reduce the unconscious bias that goes into evaluating candidates at the screening stage," she says.

4. Consider resume alternatives.

A resume tells only part of a candidate's story. If you're looking to hire software engineers, try HackerRank, which allows companies to attract talent through engineering challenges and open competitions. "This can attract a lot of great talent who aren't necessarily looking for a job but are willing to solve a fun programming challenge in their free time," she says. "And it can also surface people whose resumes aren't impressive, but who have those hard technical skills that you're actually looking for and can prove it." She also suggests video interviewing platform HireVue, which gives candidates a chance to demonstrate communication, interpersonal, or creative skills that may not come across on paper.

5. Use predictive analytics.

In other words, mine big data to predict who will be the best candidate. Pomello specifically looks at culture fit, which can be difficult for interviewers to analyze. It surveys candidates and ranks them with a compatibility score, identifying the patterns and qualities of people that make for success at your company. As for referrals, Simppler is a data-driven referral platform that analyzes the keywords and requirements from your job post to prompt employees to refer their friends.

"One problem with these systems is that they can still miss candidates who don't fit the pattern, those without the perfect, pedigree keywords," she says. "Companies should take care not to let these kinds of systems set them back on their efforts to diversify, or drive them to bid on the same narrow talent pool with lots of competing companies."