Study the type of psychology paper you have to write. A psychology paper could be a report, review, critical analysis or research report. Review the required format and make sure you adhere to the requirements of the assignment, such as word count.
Pick a topic and stick to it. If, for instance, you are writing about "obsessive compulsive disorder" do not stray off track and start writing about "borderline personality disorders" or "depression."
Draft your psychological essay. Always write in complete sentences and use concise, easy to understand English. Do not use a big word when a small one will do and avoid run-on sentences.
Avoid jargon and slang. Psychology has words that are specific to the field, so use them because it shows that you can speak about the topics, but steer clear of catchy words or pop phrases.
Use the past tense for the abstract, introduction and method. You can use the present tense for the results and discussion sections.
Work on your topic sentences. The first sentence of each paragraph is the most important, so try to make it strong and topic-related.
Do not use contractions when you are writing a psychology paper. "She can not" is acceptable; "she can't" is not.
Leave the draft of your psychology paper for a day or so and then edit it for grammar and typing mistakes. Ask a friend with good editing skills to proofread it for you. If she cannot understand the paper, consider rewriting it as psychology papers should clarify, rather than confuse.