Write a paragraph that introduces the subject of your critique. This is only necessary if the critique is going somewhere other than the people you are critiquing. If, for instance, you're critiquing a book, this paragraph would talk about the name of the book, the author and a brief overview of the book's subject matter.
Write two or three body paragraphs that discuss the book or performance. If the critique is for the public, highlight the good and bad points of the performance. If the critique is for the performer, write about the positive aspects of the performance, using appropriate comparisons when possible.
Write about the negative aspects of the performance. Express ways in which you feel the performance could be better. It is acceptable to highlight your own experience if it relates to the performance, but keep an open mind as you point out a performance's flaws.
Close your critique with a definite recommendation. If the critique is being used as a public review, state directly whether you recommend the book or performance. If the critique is for a performer, suggest avenues he might follow to expound upon the earlier suggestions you made for improvement.
Structure the critique in written form as a double spaced paper if you will present or publish it. For publication, double space the critique and use a standard font, such as Times New Roman or Courier. No headings are required for the various sections. Present the critique in a more conversational tone if you are giving it in person, such as at an audition for a performance or in a speaking situation. In this case, know your paper well enough to be able to paraphrase what you've written rather than reading straight from the paper.