One of the best things you can do when starting a research paper is start on it as soon as possible. The more research you are able to do, the more material you will have to determine how to narrow your topic and what information you want your paper to focus on. It is important to have an idea of what you want your paper to be about so once you start researching, you can determine if you need to narrow or broaden your topic. Keep your thesis in mind as well when you research. Having a rough thesis can help point you in what direction to go, and whether or not you want to change it based on what you have discovered.
Here is a simple step by step guide to writing a research paper. (From Study and Thinking Skills in College by Kathleen T. McWhorter)
The thesis is one of the most important parts of your paper. It is a short phrase summarizing your paper. Your thesis should tell the reader two things: 1. What your paper is about, and 2. why they should read it. A thesis is not a blanket statement. It should express the author's stance on the topic or explain the specifics of the topic your want to focus on. Below are some good and bad examples of thesis statements taken from the Prentice Hall Reference Guide by Muriel Harris and Jennifer L. Kunka.