Reference checks come at the end of a hiring process, which is why candidates often treat them as a formality. They usually are, until a vague or lukewarm reference stalls an offer. A little preparation makes them work for you.
The last question matters most. Hesitation there is noticed far more than any specific weakness.
Pick people who saw your work closely and recently: a former manager, a peer you collaborated with daily, and, for leadership roles, someone who reported to you. A famous name who barely remembers you is worse than a mid-level colleague who can give two concrete stories.
Always ask before listing someone, and never list your current manager without being sure your search can be known.
Send each reference a short note: the role and company, why you're excited, and two or three things the hiring team cared about in interviews. For example: "They asked a lot about how I handled the data migration and about mentoring juniors." Then remind them of a specific project you did together. You're not scripting them; you're jogging their memory so their examples line up with your interviews.
If there's a known rough patch, like a project that slipped, mention it to your reference and to the recruiter yourself. A consistent account from both sides ("it slipped, here's what changed afterwards") reads as maturity. A surprise reads as concealment.
Thank every reference, and tell them the outcome. You'll likely ask them again, and people help those who close the loop.
Disclosure: I'm on the team behind an AI job interview assistant at Linkjob AI. The advice here is general.