My high school English teacher, Mr. Mosher, gave every student a copy of this the day we entered his English 10 class.
It has saved my butt more times than I can remember. Memorize this and you can't go wrong. (At least I hope you can't go wrong.)
NOTE: TP-CASTT only deals with how to write the introduction of a critical analysis. The rest is up to you.

TP-CASTT: A Method for Poetry Analysis by Connie Vermeer
Title: Examine the title before reading the poem.
Paraphrase: Translate the poem into your own words. Resist the urge to jump to interpretation. A failure to understand what happens literally inevitably leads to an interpretive misuderstanding.
Connotation: Examine the poem for meaning beyond the literal. Look for: imagery, symbolism, irony, character developent, metaphor, personification, and similies.
Attitude: Examine both the speaker's and the poet's attitudes. Don't confuse the author with the persona. Look also for the poet's attitude toward the speaker, other characters, the subject, and the reader.
Shifts: Note shifts in speaker and attitude. Look for occasion of poem (time and place), punctuation (dashes, periods, colons), stanza divisions, changes in line and/or stanza length, and irony (sometimes irony hides shifts).
Title: Examine the title again, this time on an interpretive level.
Theme: First list what the poem is about (subjects); then determine what the poet is saying about each of those subjects (theme). Remember, the theme must be expressed as a complete sentence.

The following explains how to use the TP-CASTT chart.
1. The first sentence of the introduction must be a general statement that indicates something about human nature. From your TP-CASTT chart, this would be your theme statement.
2. Sentence two, must be a continuation of what you have stated in sentence one. This sentence must show the result(s) of what you have written in sentence one.
3. Sentence three must introduce the name of the story/poem/book, the name of the author, the characters, and the situation that is involved. A way that you might use to introduce this information could be: "In the short story (title), (author) introduces the reader to (character), who (whatever he/she did)." Remember that you may never introduce anything about the story before this sentence.
4. The next three sentences should describe what happened in the story. From the TP-CASTT chart, this would be the paraphrase.
5. The final sentence of the introduction is the thesis statement. This sentence states exactly what you will discuss in the following paragraphs of your essay.