Decide on the type of essay you're writing. You can write an analytical, expository or argumentative paper. Analytical papers break down and evaluate an idea or issue and present it to readers. Expository essays try to explain something to readers. Argumentative essays take a stand on an issue and support it with facts and evidence.
Determine what direction your paper will take. This can be deciding on a topic, and taking a loose stance on that topic. You don't want to formulate a thesis at this stage. If you develop your thesis before thoroughly researching, you'll only research attempting to prove your thesis, which can lead to a flawed paper. That said, it's okay to develop a loose working thesis. Just keep in mind that you want to remain as objective as possible on your topic.
Research your topic. This will likely be the most time-consuming step. You should only use the most credible resources when researching. The most trusted websites you can use when researching are .edu and .gov websites. If you're also using books and journals, then stick to texts printed under a university press. Universities hold higher standards for what they publish, and works are reviewed by other experts before publishing.
Develop a thesis. Once you've researched thoroughly, you should have a claim you can make or a side of an argument you can represent. This is your thesis, and it should follow the criteria presented in the introduction.
Outline and write your essay. You should always outline first since it helps you present your information logically. Then, you can easily write your paper following your outline.
Revise your thesis if necessary. Sometimes when you finish a first draft, that's when you finally realize what you truly want to write about. If this is the case, then develop a new thesis and rewrite your paper under this new thesis.