Provide a legend for the pie chart so that the reader can easily grasp what each portion represents. Legends that explain what each of the slices are should be set well away from the chart. Use a sans serif font for all text to make it easy to read. Make sure you have labelled the chart (e.g. Figure 3). Provide a title for the chart. It's usually better to place it below the chart so that the text is distinct from it. Provide any explanatory notes below the chart - but keep these to a minimum.