1. Remember that getting defensive about your manager's criticism is pointless. Arguing with your boss about your review and trying to prove that you are right and he/she is wrong is likely to do much more harm than good. Your superior is entitled to his/her subjective opinion of your performance. Just because you disagree with it or believe it's unfair doesn't make that review invalid, even if it is clearly unfair. Instead, make your manager want to help you. Ask him to guide you more specifically which areas of you work your need to improve and how you can best accomplish it. Ask your manager for specific steps you can and should be taken to address the issues in your performance. While some reviews contain objective data, such as sales figures, attendance, etc.., many other reviews contain generic, inherently vague criticisms, such as "poor leadership skills," "lack of motivation" etc. Request that your manager specify what it is that you do specifically that make him/her think that you are lacking in motivation or that you are not a good leader.
2. If you suspect that a bad performance review is issued for retaliatory reasons, start keeping track of all the important documents and communication/e-mails, so that later you have proof of retaliation. Also consider complaining about retaliation to your human resources department, especially if you had a perfect performance record prior to engaging in a protected activity, and as soon as you complained about discrimination, harassment, or retaliation, your performance all of a sudden "slipped."