Avoid These Rookie Interview Mistakes

I recently had a conversation with a hiring manager who personally interviewed 300+ people in the last 2 years. We discussed how uncomfortable it is when people make some truly rookie interview mistakes. People think the interviewer has the easy job, but it's just as stressful for them. It's not fun to watch someone make a mistake in an interview that you know is costing them the job. Trying to keep a poker face and finishing the interview can be tough. Here are some of the top mistakes we both have seen first-hand:

1. Failing to do any research on the company so they are unable to answer the most basic question, "Tell me what you know about us?"
2. Making the first question when it's their turn to ask questions, "What's the job pay?"
3. Showing up under-dressed, looking disheveled and chewing gum.
4. Arriving clearly hungover, sick, and smelling of booze.
5. Taking calls and/or texting during the interview.
6. Showing up late.
7. Trash-talking a former employer.
8. Swearing.
9. Telling the employer what they think they are doing wrong in their business model without being asked for their opinion.

Interview = Thousands of dollars ($$$) on the line.
Interviews are hard to come by. Each time we fail to fully prepare for an interview, we are putting an entire year's salary (and more) on the line. Even if we aren't excited about the job, it's still worth it to prepare. Who knows? They may have a job that isn't posted that we'd be perfect for. Or, they may remember us when a job does come available that we're a better fit for. No matter what, there's no excuse for not preparing for any interview that comes our way.
And yet....
How many times have smart professionals chosen to "wing it" in an interview? I hear justification for the lack of preparation all the time. Things like:
"I'm better when I don't sound rehearsed."
Or, "I don't want to look to over-the-top about the opportunity."
They forget the cardinal rule: in an interview, you are a business-of-one and the employer is your customer. If you don't show them you're working hard to earn their business, why should they bother picking you?
I'm not suggesting we put the employer on a pedestal.
I'm saying the best way to show the hiring manager we want to work "with" them and not "for" them is to come to the table ready to prove ourselves worthy of a partnership.
Don't you agree?
I'm curious, what's other rookie mistakes have you all seen or heard of? Please share them in the comments below.

J.T. O'Donnell

Founder & CEO of CAREEREALISM.com | Creator & Coach at CareerHMO.com | Syndicated Author | Columnist | Blogger | Speaker