Think of the CAP as a well-researched persuasive/argumentative paper.  Imagine that you are trying to persuade an intelligent, but uninformed reader of your conclusion, which is encapsulated in your thesis statement.  The last sentence of your introductory paragraph should be your thesis statement.  A common problem that I see is that the thesis statement is way too broad.  Be sure to narrow it down sufficiently to write a well-written paper in 4-6 pages.
The paper should consist of the reasoned defense of some claim, which is stated in your thesis statement.
A good paper is modest and makes a small point; but it makes that point clearly and straightforwardly, and it offers good reasons in support of it.
Make the structure of your paper obvious.  Include a short outline of the main points of your paper.
Be concise, but explain yourself fully.
The paper has to do substantive work, not merely regurgitate an authors main points (although, of course, it is important for you to restate an authors position before criticizing it).  Some possibilities are:
Criticize an argument; or show that certain arguments for the thesis are no good.
Defend the argument or thesis against someone else’s criticism.
Offer reasons to believe the thesis.
Offer counterexamples to the thesis.
You must cite at least two academic sources (such as journal articles, books, websites, etc.).  Make sure those sources are academically reputable.  Since web addresses change constantly, you can find the website by googling its name.  Be careful of satire websites or fake news.  Some good websites include the Stanford Encyclopedia of Philosophy, Internet Encyclopedia of Philosophy, Philosophers Imprint, and the numerous electronic databases that the school library carries.  Possible outside sources include books, journal articles, magazines, databases, Websites, videos, dictionaries, encyclopedias, and almanacs.  When possible, try to cite from recent sources. Make sure you evaluate your online sources for trustworthiness and credibility.
Papers should either be in Microsoft Word format (.doc).  Upload to Canvas by the due date towards the end of the semester.
Four-to-six pages, double-spaced, Times New Roman font, 12-point, one-inch margins.
MLA or Chicago system of citation.
Include a cover page that contains the title of the paper, your name, my name, the date, and the class (e.g., PHIL 1301.710 or MW 10:10 AM). 
Include a short outline of the main points of your paper and include it after the title page.
You are allowed to write in the first person.
Regardless of which topic you choose, make sure that you provide a thesis statement in the introductory paragraph.  It tells the reader the main point for which you’ll be arguing in your paper.  A common problem that I see with some thesis statements is that they tend to be overly broad.  An example of a broad statement would be something like the following:  “In Book 1 of the Republic, Socrates criticizes several people and ideas.”  An improved thesis statement (because it narrows the scope of discussion) would be something like the following:  “In Book 1 of the Republic, Socrates’ first attack on Polemarchus’s definition of justice is unsuccessful because Socrates erroneously assumes that justice is a craft.”  Assume that your reader is intelligent, but uninformed.  This means that your reader is very capable of following your arguments, but he or she just needs sufficient explanations to help them understand the philosophical topic that you’re discussing.