It is a very interesting question you have put forth here- I am currently involved in one such venture for Dengue in my State- and hopefully my data sets should be out by the end of this week.

I think one can reasonably identify the areas at high risk and draw logical conclusions as to why the incidence is high in certain areas.

A methodical approach should begin with a layout of your goals- 1) What do you want to study. 2) Will you have field team support?. 3) What all parameters will you include? 4) What is the number of subjects you are looking to include? 5) Any chance of follow up studies on a year-by-year basis?

Start by keeping things simple. Prepare you basic format for questionnaire and excel sheets for data input.

Identify parameters you want to include.

Always have the addresses of the subjects included in your analysis

Have a detailed map of the area of study- blow it up to 2x or 3x scale for easy marking.

Go through other studies conducted on your area.

Think out of the box- think of ALL possible causation for outbreaks in an area- be familiar with the disease

talk to people in the area- ask what THEY think could be contributory.

As and when data is available- build up your database.

Be patient- it takes a lot of effort.

Keep in regular touch with your peers - ask ask and always ask about their experiences and kind of patients they are encountering.