When looking for the real estate professionals to bring onto your team: lawyer, CPA, agents/brokers, lender, contractors, etc. how do you know what makes a good hire? How do you know what makes a quality person vs. someone who doesn't know what they're doing?

Most of these people are only brought on when needed and for most people aren't full time "hires"  so it is similar to how one selects a contractor get some bids and talk to the people.  For things like a realtor, most can do the basics so you look for things that are important to you like connections with GCs or the ability to understand what makes a good investment.