Free-writing and clustering are two warm-up writing exercises. They not only help the brain to warm up and begin focusing on the topic at hand, but they also serve to help the writer generate and organize ideas that can later be used as the basis of an essay or research paper.
To begin free-writing, first start by writing down the topic at the top of a piece of paper or on a computer. This can either be one or two words (trees, morals, airplane food), or it can be a brief summary of the topic. Next, set a timer for a period of time, such as five, seven, or ten minutes. Now start writing or typing without stopping. Do not worry about writing in complete sentences or about spelling mistakes. Do not worry about making grammar mistakes or where to put the comma. And do not judge what you have written down. The point is to continue writing for the entire period of time without censoring yourself as to what to write. Everything written down when the timer goes off may not be related to each other or even to the main topic, but your brain may generate fantastic material that would have remained locked up if it had been censored.
Another pre-writing exercise is called clustering. Clustering involves writing down words or short phrases with the intent of finding similarities between ideas. These can then be used in an essay or to help write a thesis statement. Begin by writing the topic or idea in the center of the page. Then write down any words or phrases you can relate to the main topic. From those words or phrases, write down other connections. Keep writing and making connections until all ideas are exhausted. It may help to circle or group similar ideas together, or to write down familiar ideas in the same color ink. The end result may look messy with lines and circles drawn to connect ideas, but do not cross anything out, as that may be the best idea of all!
If you have problems with free-writing or clustering, or you do not find the techniques helpful at first, continue working at it. Like anything else, you will get better at it over time.