Suppose you are interested in how Waterville was affected by the Great Recession. You initially begin by looking a newspaper articles for ideas. While there are many possibilities, you decide to look at child poverty rates.
Because this is demographic information, it is likely to be included in the census, available from American FactFinder. You create an advanced search, breaking your question into parts
1. Information about poverty
2. Information about age
3. Information about location
4. Information about time
The first two pieces of information are easily found in the "People" topic of the search builder. Location is more difficult. Waterville's ZIP code isn't listed, and if you choose "Waterville City" under the place menu, you are unable to get data from before 2009. You figure out that data for the "Augusta-Waterville micropolitan statistical area" will meet your needed time frame, so you adjust your question to work with the available data. You select years 2005-2011, to have data for 3 years before and after the pivotal 2008 year for the recession. You decide your best dataset option is "Poverty Status in the Past Six Months by Sex by Age".