So, here’s a list of common blunders to avoid.

Gaffe #1: Being Late

Why it’s a red flag: Being late indicates a lack of organizational skills and perhaps a lack of commitment. Will you show up on time for work?
Handle it better: Get specific directions to the interview up front and ask about parking. Allow a cushion of at least 15 minutes on the interview day.
Damage control: Still running late? Start by calling the interviewer as soon as you know you’re not likely to make it on time. Explain, apologize profusely, and demonstrate flexibility by asking if they would like to rebook.

Gaffe #2: Dissing the Help

Why it’s a red flag: If you can’t treat everyone equally and be civil during the interview process, how are you going to handle customers and fellow colleagues?
Handle it better: Treat each individual in the recruitment process with respect, from the secretary to the test administrator.

Gaffe #3: “Sorry, I Haven’t Had Time to Google You Yet.”

Why it’s a red flag: If you haven’t done your homework beforehand, you’re giving the impression you’re not interested in the company.
Handle it better: Be prepared. Look at the company’s website or check out its products, and come up with a list of savvy queries about key business issues or crucial skills needed for the job.

Gaffe #4: Exaggerating

Why it’s a red flag: We all want to look good in an interview, but if your future employer discovers that you’re not telling the strict truth, your credibility will be damaged. Taking all the credit is a good indicator you might not be a team player.
Handle it better: Make sure to be honest about your achievements and be sure to include team members.

Gaffe #5: Show Me the Money

Why it’s a red flag: It’s a turnoff for most employers if you’re only in it for the money. The first question you ask about a company should not be: “What are the salary and benefits?”
Handle it better: Salary is a touchy issue. Stay flexible, let the interview progress and then bring up salary. Once you have a firm job offer, you can negotiate. If the company really wants you, there may be wiggle room in salary

Gaffe #6: “My Last Boss Was Such a Jerk!”

Why it’s a red flag: Being critical of a previous employer rarely sits well with a potential one. It makes you look like a negative gossip. Even worse, if you’re applying for a job in the same industry, there’s always the chance your interviewer knows the person you’re slagging.
Handle it better: If a potential employer asks you to tell her about a difficult work situation keep it succinct and positive, take some of responsibility for the problem, and be sure to discuss the solutions you came up with.

Gaffe #7: Getting Emotional

Why it’s a red flag: If you get emotional or seem too needy during the interview, the employer may worry you can’t keep your personal life separate from work.
Handle it better: When the interviewer asks you about a tough situation in your life, stay focused on the matter at hand. There's no need to get personal.

Gaffe #8: Ramblin’ On

Why it’s a red flag: Yes, the interview is about you, but you can appear self-centred if you go on and on.
Handle it better: Internet job sites like offer sample interview formats. Do a practice interview with a friend or relative and develop your appropriate responses, as well as a few questions. Keep your answers short but informative. At the end of the session, most interviewers will ask if there’s anything else you’d like to tell them. If you’ve missed some highlights, this is the time to raise them.

Gaffe #9: “I’m Perfect.”

Why it’s a red flag: The classic interview question—“What are your weaknesses?”—should not be answered with “I don’t know.” Employers want to know you are honest and self-aware.
Handle it better: Be honest, forthright and self-critical, but also show what you are doing to improve that weakness.

Gaffe #10: Desperation

Why it’s a red flag: Being over eager or over anxious can harm your chances of getting the job. We all need to work, but that’s not the issue. You have to demonstrate what you can do for the company in an interview. If you’re desperate, the employer may conclude that you’re not a top-quality candidate.
Handle it better: Be sure to send a thank you note after the interview. If you feel you blew the interview, add a short, factual list of the things you could have articulated better. Wait three or four days to call, unless directed otherwise.