1. Here is a great resource from University of North Carolina's Philosophy Department: http://www.unc.edu/depts/wcweb/handouts/philosophy.html
2. Here are my own, basic suggestions for writing a good paper:
Philosophical essays generally require no special skills beyond those necessary for any effective essay that supports a specific thesis. The following are just reminders of the most important strategies for the task. For more detailed discussion of principles of clear writing, I cannot recommend highly enough The Elements of Style, by William Strunk, Jr. and E. B. White.
1. State your thesis clearly and support it well.
As an argument must have a specific conclusion that follows from specific premises, an essay must have a specific thesis that is supported by specific evidence. It is best to make your thesis clear at the beginning of your paper, and to indicate there, in brief, the evidence that you will consider. Evidence includes explanations, arguments, and definitions as well as facts.
2. Keep your priorities straight.
Every essay is limited by considerations of space. Therefore good judgment is necessary about what to include. All information that is necessary for establishing the thesis must be included, and all irrelevant information must be excluded. Everything else will be more or less important, and your task is to judge which information is more important, and include as much of it as limitations of space allow.
3. Make the paragraph the unit of composition.
Each main point in your essay deserves its own paragraph, and each paragraph must have one clear main point. Each paragraph must add something new and significant to the establishment of the thesis. The relation of each paragraph to what precedes it or to the whole should be clear. Paragraphs must be composed entirely of complete sentences, each of which contributes to the main point of the paragraph.
4. Concision promotes clarity.
Always state your points as concisely as you can without sacrificing necessary information. This requires stating your points simply and directly; using the active voice; omitting all needless words; and avoiding vague and flowery language. Concision almost invariably makes writing more clear, because it demands that you keep your priorities straight at all times, even within each sentence.
5. Use statements, not questions.
Questions are seldom appropriate in an essay. Avoid the temptation to include rhetorical questions: they assume that the answer is obvious, whereas your essay is supposed to explain what is not obvious. In general, questions add little to an essay, because arguments and explanations must be composed of declarative statements.
6. Draft and revise thoroughly.
Every essay will always benefit from a thorough revision for clarity and concision. The first way of stating a point that comes to mind is seldom the best way to state it. When revising, keep in mind the purpose of the essay as a whole and the role of each of the parts. Don't just tinker with the sentences and paragraphs that are present in the draft; serious revision requires reorganization as well as rewording.
7. Non-obvious ways to check for quality.
Revision for clarity and concision will be helped by the following techniques. Use as many of them as you can: (1) have a smart friend or roommate read your paper over before you write a final draft. If your paper is on the right track, they should be able to understand your main point easily, summarize your argument in brief, and not be confused at any point in the paper. Encourage them to be brutally honest about your paper. (2) Read your paper aloud to catch errors; if possible, read it aloud to a friend. Don't underestimate how useful this can be! (3) Always spell-check your paper.
(This is adapted from notes by Dr. Glenn Rawson)
Tips on Proofreading: Format and Organization
(adapted from http://www.brighthub.com/education/homework-tips/articles/36439.aspx)
Proofreading is one of the most important parts of essay writing. Using these tips on proofreading will help you avoid common essay pitfalls.
Begin by checking the format/organization of your essay. Poor organization can hurt a good paper.
Do you have the correct/minimum number of words and paragraphs for the assignment?
Are the spacing, margins, font, and footnoting style in accord with the instructions?
Does the essay have a title?
Does each paragraph have a clear topic?
Does each paragraph begin with a topic sentence and end with a concluding/linking sentence?
Are each of the topics discussed in logical order?
Tips on Proofreading: Mechanics
Next proofread your essay for good grammar and sentence structure. Unclear sentences and poor grammar detract from the presentation of your ideas.
Are there any run-on sentences or sentence fragments?
Does every sentence make sense when read aloud?
Are sentences punctuated correctly?
Are there any slang words, double negatives, or misspellings?
Is the verb tense the same throughout the essay?
Tips on Proofreading: Content
When proofreading, it is also a good idea to check your content. You want to be sure that your paper says what you meant it to say and says it authoritatively.
To what degree does the paper just sound like casual opinion? In other words, are you taking the trouble to back up your assertions and judgments with examples or relevant quotations, etc.?
Are all quotations accompanied by your explanation/analysis? (Don't just drop in a quotation and then move on.)
Does your essay clearly address all the points asked for in the assignment?
Does your essay stay focused on the assigned/chosen topic?
Does your essay have, early on, a thesis statement (a clear statement of your main point)? Does it conclude with a summation or overall assessment or does it just stop?
Has all material from outside sources (quotations, sentence structure, ideas, etc.) been properly cited?