It is easy to fall into the trap of thinking that writing essays is simply a matter of having an idea and then writing for a while. Even if you know that it's more than that -- a process involving some research, maybe an outline and a draft or two -- it is easy to produce a paper that does not receive the grade you want. There are, however, nine steps that you can take that, if you follow them through, will almost certainly guarantee a high B if not an A.
Step 1: Find a Topic that You Want to Write About
The key to a great paper is writing about something that really interests you, something that will make you excited about working on this essay. This will allow you to bring a great deal of energy and insight to your topic and ensure that you give more than enough effort to completing each of the following steps. Almost every student falls into the trap of assuming that.
It is unfortunately very easy to convince yourself that essay assignments are 'just assignments' and not intended to engage your enthusiasm, but nothing is further from the truth. The trick is to find a way to make your own interests bear on the topic at hand. Even the most strictly assigned topics allow the room to bring whatever information you want to address them. Be creative. There is a reason you wanted to take this class, so use that as a way to find an exciting topic.
Step 2: Start Reading Everything You Can!
The purpose of an essay is to communicate a single statement: your thesis (see below). You will find it very difficult to find out what statement you want to make, though, without knowing at least something about your topic, so after finding an exciting topic you will need to form some ideas about it by reading everything you can get your hands on. Sometimes these two steps interact with each other as your reading changes your interest, but usually you will know what you like and want to stick it.
Step 3: Devise a Working Thesis
After you've decided on a topic and acquired a bit of knowledge relating to it, you will then be able to come up with a single sentence that you know is true beyond any doubt. Often it will seem so obvious that there seems little reason to argue it. This is the perfect thesis. Imagine yourself having a discussion about your topic with someone who is totally impatient. They want to know everything you have to say but only want to hear one sentence. That is your thesis, and your whole paper will fall into place once you know it.
These three steps form the foundation of all your future work, so make sure that you are really comfortable with these. They should feel right and make you actually excited to see where your project leads you. Ultimately, you're using the essay to learn more about your topic, so pick one that makes you excited for the hunt!
(next 3 steps, coming soon!)