The IT job market is improving, and CIOs are once again looking to hire permanent, full-time IT staff. But because the labor market is saturated with IT pros looking for work, IT hiring managers are being choosey, say IT staffing industry experts.\nMake one mistake on your r\u00e9sum\u00e9, and you can forget about being called for an interview. Fail to impress during the job interview, and the hiring manager may cut your meeting short. Go dark on a prospective employer after a job interview, and you can kiss your chances of getting a job offer good-bye. Yes, my friends, the stakes are that high. \nExperienced and inexperienced job seekers alike make mistakes before, during and after job interviews that can sink their chances of landing a new job. Tracy Cashman, partner and general manager of the information technology group at staffing firm Winter Wyman, says she has seen candidates get eliminated in the past month for making such mistakes as speaking ill of a previous employer and asking about vacation and benefits too soon. \nMost of the missteps job seekers make are common and can easily be avoided with a dose of common sense or preparation. Here are seven ways job seekers self-destruct. \n1. They lie about their qualifications. If anything will kill your chances of getting a job, it's lying, whether on your r\u00e9sum\u00e9 or in a job interview, whether about your skills, employment history or educational background. "Lying on a r\u00e9sum\u00e9 will get caught on a background check," says Cashman. "We had a candidate, a fresh graduate, lie about their GPA, and the employer rescinded the offer." \n2. They come to the job interview unprepared. Todd Collier, a director with IT recruiting firm Eliassen Group, says his firm spends time prepping candidates for job interviews. He says Eliassen briefs candidates on the project they'll be working on, the employer's business and culture, and the manager's needs and style so that the candidate knows how to sell him or herself during the job interview. "People miss out on job offers when they don't fully understand the company's needs," he says. \nAdds Cashman, "It's so easy to do [research on an employer] these days that if you walk in without knowing basic information about the company, you just look stupid or like you're not interested in the job." 3. They're negative. Having a negative attitude or speaking ill of a former employer is a common mistake job seekers make during job interviews. It's one that Sam Aruti, managing director of DIBJ Enterprises, made in the past when he was looking for a job, and it cost him an offer. \nWhen a job seeker speaks poorly of a past employer, prospective employers wonder how long it will be before the job seeker begins denouncing them, says Cashman. It also causes employers to worry whether the candidate will ever be satisfied. \nCashman advises job seekers to use caution when speaking about their reasons for leaving an employer, which can easily come across as negative. State one reason and keep the explanation brief. \n4. They don't ask the right questions. Job seekers who ask informed, specific questions about the job or the employer during the interview impress hiring managers. "It's always nice to hear people ask questions that are relevant to the company," says Aruti, speaking as a hiring manager. \n"Even if every question you could ever want to ask has been answered during the interview, have two more questions," adds Cashman. "Otherwise, you look uninterested in the job, and it leaves the hiring manager on edge. Good questions are definitely seen as the sign of a good candidate." \n\nBut don't ask about vacation time or benefitsat least not during the first interview. Aruti and Cashman say doing so makes hiring managers think benefits are all you care about, so they won't take you seriously and you'll quickly get passed up for the next candidate. \n"As someone who'd been out of a job for such a long time, if you have a job opportunity in this economy, focus on job rather than on 'what's in it for me'," advises Aruti. \n5. They're slow. Aruti always walks with IT professionals he interviews for jobs to see if they can keep up with him. He doesn't hire anyone who can't. People who are slow on their feet will likely be slow on the job. It's a lesson he learned years ago from a former manager who told him not to hire someone who "didn't walk right," he says. \n6. They don't "close" the interview. Eliassen's Collier compares job interviews to sales calls. Just as sales professionals work toward closing a sale during a meeting with a prospective client, job seekers should work toward closing a job interview, he says. They can close job interviews in a couple of ways: Either by asking if the hiring manager has any other questions about their background, or if the hiring manager gives the last word to the candidate, the candidate should take the opportunity to reiterate why he or she is an excellent fit for the job and the company. \n"Ask if the hiring manager has any other questions about their background as it relates to the job opportunity," says Collier. "Is there any reason you don't think I'd be a fit for this opportunity? Then, they can expand upon it and position themselves for the opportunity." \n7. They go dark. Not following up with a prospective employer after a job interview can be fatal. It sends the message that you're not interested in the job. So at the very least, send a thank-you note after the interview, advises Cashman. It can set you apart, she adds, because most people do not send them. \nThough some hiring managers appreciate old-fashioned, hand-written thank-you notes, your best bet is to send a well-written one via e-mail. If an employer is in a rush to fill a position and faced with two equally qualified candidates, delivering a thank-you note quickly via e-mail could make all the difference, as a decision may have to be made before the mailed thank-you note arrives. Cashman has seen it happen. \nResponding too slowly to a job offer also sends the wrong signal to a prospective employer, according to executive search firm Korn\/Ferry International. They employer might think that the candidate is getting cold feet or has completely lost interest in the job. \nOf course, job seekers need time to evaluate offers. They should state up front, upon receiving the offer, that they need time to think about it, and how much time they will need. Candidates can ask for a day to a week to make a decision, depending on the complexity of the offer, the job seeker's career level, and the employer's timeframe. \nMeridith Levinson covers Careers, Project Management and Outsourcing for CIO.com. Follow Meridith on Twitter @meridith. Follow everything from CIO.com on Twitter @CIOonline and on Facebook. Email Meridith at email@example.com.