Google advanced search is a great tool for researching your race. It offers a number of useful practices that allow you to search for exactly what you're looking for, include specific site searches (your local paper, an opponent's website). Unless otherwise noted, I recommend using Google for all your research.
It's important to know what's out there on you, because your opponent will likely find out. Do a google search for yourself, review your past twitter and Facebook posts (and clean up anything that shouldn't be in there).
Review old articles you've appeared in in the local paper. Review any opinion pieces or letters to the editor you wrote, particularly in your college newspaper (college papers are beginning to put even old editions online).
If you've served in office before, know your voting record. Are there any votes you took that your opponent can exploit?
This is an easily dismissed practice, but it's important to know what's out there on you so you can prepare a response in advance.
2. Your opponent
When you think about research for a political campaign, oppo research is the first thing that comes to mind. Start by getting your opponent's full name, including a middle name so you don't accidentally accuse him of something someone else did.
Search the newspapers using Google's advanced search, and review his campaign website. Are his current positions the same as they were in a speech he gave a year ago?
Remember when researching your opponent, you're not looking for a smoking gun. Those are rare. Your goal is to define him, not attack him. You want to find a consistent pattern of contradictory statements, or of him being on the wrong side of an issue, or of him not representing the district he's running in well.
3. Your Election
Note: this can often be divided into two sections -- "the district" and "the voters"
You have to know your district well. One thing I suggest is taking a day to drive around the district with someone who knows it well. What businesses are in your district and where are the residential areas? You may think you already know your district, but you can always learn more.
Also get a precinct map of the district and post them where you see them regularly. That will help you get familiar with the neighborhoods and the precincts. You can get a precinct map from your county clerk.
Research the voting habits and demographics of the district. You can get a voter list from the county auditor or clerk, and you can get district demographics from the Census.
Twitter advanced search is a good resource for getting to know what people in your district are talking about, and so is your local newspaper. Review the local section of your paper and the opinion page for the past year or so. What issues matter to voters?
Finally, put all the information down on paper. You're more likely to remember it if you write it down, and you also have the ability to go back and review it.
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