Errors of perspective can also create unnecessary pain just like errors of thinking. The standards that people hold themselves to meeting also helps determine how they will experience events. People who are perfectionists hold themselves to very high, even unrealistic, standards. They are vulnerable to making the selective attention error and focusing on what is negative while ignoring or devaluing what is positive. Because their standards are higher than are reasonable, and because they manage to ignore what is positive, instead focusing on what is negative, they will end up failing to meet them a fair portion of the time, and will feel bad about that failure. People whose expectations are more reasonable and less perfectionist are likely to meet their expectations more often and to feel comparatively better. When you feel that getting a B on the test is a terrible thing and means you are an inadequate human being, then you will feel depressed about getting that B. If you can instead, teach yourself to be less judgmental regarding how you do in life, you will feel less depressed when results are not perfect.
Once you understand that your fear that you are "stupid" is truly unwarranted, you can tell yourself so by writing it out on your thought record. Doing so will likely help change your mood for the better. Note, however, that you have to believe the corrected responses you make; you have to know that they are true, before the exercise will help change your mood. If you write down a corrected response that you don't really believe is true, you haven't corrected anything (you're only trying to lie to yourself), and the exercise will fail.
The cognitive restructuring technique is not terribly complicated in of itself. However, many people do find it difficult to identify their automatic thoughts and core beliefs properly, and also to generate good quality corrected responses to those thoughts and beliefs. Anyone interested in trying this technique is encouraged to do more reading on the subject. A good general book on the subject is David Burns' "Feeling Good". Of course, the other good alternative is to work with a cognitive behavioral therapist who can help you identify relevant thoughts, beliefs and cognitive errors.
Cognitive restructuring is the best studied and best understood technique for changing thoughts and therefore the one we've focused on the most. It is not the only useful technique for changing thoughts, however. The next sections cover other approaches to altering thought habits which can be used independently of or in conjunction with cognitive restructuring.