Become familiar with the GRE data interpretation question layout. These questions always come in pairs. Both questions will reference the graph or chart displayed.
Study the charts and graphs before reading the question. Read the title, axis labels and keys to get a simple understanding of the data presented. This will make the questions easier to understand.
Use only the information provided in the graph or chart. Do not read more into the graph or chart than is really there. Do not base your answers on your own knowledge of a subject on the GRE general test.
Estimate values based on percentages and fractions when you can. Do not waste time doing calculations to find a value when an estimate will work just as well.
Keep track of units and what information is given in percentages versus real numbers. This will help you avoid incorrect answers involving ratios of units or quantities.
Familiarize yourself with the data interpretation questions by using sample GRE questions and tests.