A lot of hiring managers make the mistake of qualifying first, and attracting second. Qualifying first is a big mistake because then you will have less candidates to choose from.
Attraction allows you to cast a really wide net in order to find some of those great candidates. A few ways you can throw a wide net is through contacting universities and local organizations, cold calling through directories, posting on job boards, social media etc.
Don’t put requirements in your job description or drill the candidates immediately. Get people interested first, and then weed out those who are disqualified.