A specific date is much more helpful. There is no one, tried and true, cookbook approach to searching for answers. Every person has areas of information with which they are more familiar, books and reference tools they are more comfortable using. The key to successful searching begins with getting the correct question. Once you know what the patron actually wants, you can start the search.
Mind set is very important.
Instead of a list of directions you need to be able to look at a question creatively. Consider all possible terms. Use broader terms and synonyms since this opens up a variety of pathways to the answer. Think about who might know something about this subject. Mining the patron for information, going to another staff member, making phone calls to potential experts or sources of information, networking or asking others are all possibilities.