Part 1: Begin with a blank piece of paper and draw two columns. In the first column, start listing your main characters macro needs and wants. Macro needs are the overall life desires and wants of your character -- what they want to accomplish in their lifetime, or what they may be running from -- kind of like a life-mission. They could be concrete things like "to become a firefighter" or more involved and inner like "find inner peace."
Part 2: In the second column, list the micro, day-to-day needs/wants and desires of your main character. These can be routine-based like "shave every other day," or deal with particular situations in your writing like "find a plumber to fix the leak."
Part 3: Next, draw two large circles on a separate sheet of paper and begin placing the statements from each of the two lists. Keep the lists separate for now, and place the needs and desires that are most important to the character (note: not most important to your plot or what-have-you) closer to the center of your circle.
Part 4: Finally, choose four or five statements from each of the circles as jumping off points for some writing. Circle or highlight the ones that are closest to the center and write one or two paragraphs using each statement as the springboard for the subject of the paragraph.