Policy is a formal set of ideas or plans used to decide what actions, if any, will be taken regarding different issues. Individually, this might be called your personal philosophy and this philosophy help you decide how interact with the world. Policy is a more formalized collective philosophy.
Policy exists at all levels of almost all institutions. Colleges, business, and libraries all have polices. So when looking for policy it is important to consider who would be involved with the subject you are looking for.
It is also important to keep in mind that policy often changes with the person who is elected. For example The Justice Department's policy concerning how they prosecute drug crimes can be very different depending on who is the President. This may also be true for mayors and city councils, so it is important to consider the timeframe of the policy you are looking for.
There are also general policies and specific policies. When beginning your search it is important to consider the scope of what you're looking for. For example if you are looking for information on U.S. drug policy you will find a general policy about how the U.S. views drugs, but this may not be specific enough for your research. To be more specific you may want to look for drug prosecution policy.
Unlike many things that have to do with Government Information, policy is widely reported in the news and this can be a good source of information begin you search for government policy, while the specific source of information reported in the news may not always be clear, it can give you a good idea on where to begin your search.
Many government agencies will also have information about their specific policies online. This is another good place to use Google's domain search. A good strategy might be including policy in your search terms.