IQ without EQ is a Ferrari on Ice.  You have all this power but you can’t go anywhere because you are spinning your wheels.  There are diminishing marginal returns on IQ.

EQ = Personal Competence (Self-awareness + Self Management) + Social Competence (Social Awareness + Relationship Management)

Talk to your team to determine fit criteria.  What do they like about working with their colleagues and distill it into 5-10 criteria.

Avoid confirmation bias.  If you’re a procrastinator, go find the person that gets their laundry done before they run out.

Look for candidates who analyze risk in a mathematical way.  Never say no, say "Yes, but..."  Never say “I told you so”, say “I want you to remember this conversation.”