First of all, good job specifications are needed. You may have all the information in your head, but the real challenge is to clearly convey not only what the job is (its purpose and major responsibilities) but what are the qualifications that enable someone to do the job well.
Qualifications should include education, experience and knowledge; skills and abilities; and traits and characteristics. You can use something like the Predictive Index to spur your thoughts on the last item -- which may be the most important one. Personal traits and characteristics are often the most important aspect of an individual who being considered for hire. But in order to find the people with the right characteristics, you must first identify what is most desirable. Having hired one star already, you might want to study what personality characteristics he has that make him so outstanding as an employee. Is he highly intelligent, self-motivated, conscientious, forthright, outgoing?
Not every job will require the same exact traits any more than every job requires the same education, experience and knowledge. However, there may be a common "profile" that appeals to you for every member of your team. Do your best to determine what that profile might be and then hire people that fit that profile -- even if they fall a little short on your ideal benchmark for education, experience and knowledge or skills and abilities. That is your gut trying to tell you what is most important to you.
Using behavioral assessments can work well. Not all are created equal. Find one that is validated, that measures the personality traits that are important to you. Then, if you take the assessment and understand your profile in key areas that relate to your passion for the business, you should be able to find people whose mindsets are similar -- not identical, perhaps, but close enough on the important traits to make them good fits for your company team.