Formulate your hypothesis, an assertion of the point of view you intend to prove. It might directly and simply answer the question in the SAT essay assignment --- positively or negatively --- or respond to one of the statements in the prompt paragraph. For example, turn the question, "If people worked less, would they be more creative and active during their free time?" into a thesis sentence such as "Shorter working hours free up both time and energy for creative activity."
Plan out the evidence --- "reading, studies, experience or observations"--- you will use to test your hypothesis. It doesn't all have to support your idea. In fact, it will strengthen your case to acknowledge evidence that does not support your point of view. In the actual SAT test setting, you cannot do additional research, but when you're practicing or writing another kind of essay you may come across questions that you would like to answer. Make a list of your evidence and rank the items by the strength of their arguments for and against your hypothesis.
Draft a paragraph summarizing your negative evidence. For the thesis sentence in Step 1, you might refer to summers off from school that you squandered when you were offered opportunities to learn to play guitar or paint in oils. Think about how your friends spent their extra time in those same summers.
Assemble additional paragraphs on each of the points in support of your hypothesis. For instance, when you did get a summer or after-school job, did you gain greater appreciation of time off and put it to good use? Again, use all the material you have and present it persuasively. If you can directly counter each negative point, you will have the strongest argument.
Summarize the evidence in a concluding paragraph, and finish with a strong restatement of your hypothesis.