
Confirm anonymity: First and foremost, do not forget that you would like to cite some people from this company, most probably your immediate manager, as your reference for a future opportunity. Hence, it pays to ensure that your comments during the exit interview would remain anonymous. After all, you don't want to tick someone off and ruin your chances of getting a good reference when all you intended to do is give your honest opinions about what went wrong with your job.
Be prepared for the standard questions: Everyone knows that HR managers conduct exit interviews to take your feedback on what went wrong at your job, why you decided to move on, and what, if anything, could have persuaded you to stay. Hence, prepare your answers to these questions beforehand just so that you don't get carried away during the interview and end up saying things that you did not intend to. After all, nobody likes a rant and stops paying attention to it after a few minutes.
Be diplomatic and solution oriented: What you definitely do not want to do during an exit interview is start pointing fingers at team members and the management. Remember it is an exit interview and not a complaint session. Speak out the concerns that you have regarding the ay things are run, but instead of complaining give suggestions for improvement. Instead of saying that people do not know how to manage projects at the company, say that the company will benefit by hiring a few experienced project managers and streamlining the project management process. HR managers appreciate it when they are given recommendations for improvement instead of rants. At the end of the day, the purpose of an exit interview from the HR point of view is to collect suggestions for improvement so that the company can create a more employee-friendly environment and thereby decrease its employee turnover.
Before stepping in for an exit interview, remember that HR managers appreciate your taking out the time to give them thorough and thoughtful feedback. So, make the most of this opportunity to make a difference to the company even when if it were your last day there.