1. Are they flaky or reliable? Do they get back to you by when they say they will? Does the job description seem set, or is it constantly changing? Are other details consistent, like who you'll be reporting to or interviewing with? If they're flaky now, guess what they're going to be like to work with?
2. Are they able to make decisions? Or, are they they unable to make a hiring decision after multiple interviews? Is there always "just one more" person you need to meet with? Do they seem hesitant to commit to any candidate, and instead drag the process out for months and months? You want to work with people who can make decisions.
3. Are they considerate? Do they offer you something to drink when you arrive for your interview, or do they act like you're an unwelcome interruption? Do they ask you to do inconvenient things, such as interviewing on just a few hours notice, without acknowledging or apologizing for the inconvenience? Or, do they take your schedule into consideration, too? Do they update you when their own timeline changes or leave you in the dark?
4. Are they friendly? Do they seem like people you'd want to work with? Unless the position requires the ability to perform in a hostile or pressure-filled situation, good employers will be welcoming and will try to put candidates at ease.
5. Are they candid about the job or do you feel like they're trying to sell you something? Smart employers will be honest not just about the upsides of a job, but also about the downsides. Employers who try to downplay the less attractive aspects of the job—such as boring work or long hours—end up with employees who don't want to be there. Look for truth in advertising.
6. Do they keep you informed? Are they clear about what you can expect from their hiring process, or leave you constantly wondering what, if anything, will happen next? Too many employers don't even bother to let applicants know that they're no longer under consideration. I could come up with a business justification for why this is bad (it risks alienating a future customer or someone who could be perfect for a future opening), but the bigger point is that it's rude and inconsiderate.
Pay attention to the little things. They're giving you clues about much bigger things.
Alison Green is the author of Managing to Change the World: The Nonprofit Leader's Guide to Getting Results. She is chief of staff for the Marijuana Policy Project, a nonprofit lobbying organization, where she oversees day-to-day management of the staff as well as hiring, firing, and staff development. Her writings have been published in the Washington Post, the New York Times, Maxim, and dozens of other newspapers. She blogs at Ask a Manager.