1. Pick a very interesting topic to you. Be creative and don't just grab the first thing that comes to mind or sounds the easiest to do.
2. MAKE SURE you get a large sample, because small samples can give you data that isn't necessarily representative of the population.
3. When choosing a method of obtaining data, whether survey, direct observation, etc. be overcritical of your method and try to eliminate any bias.
4. Get as much data as possible that is related to your subject, you may find new correlations or interesting trends that will make the report much more informative.