The reason for searching an electronic database is to find something. Here, the discussion is mostly about finding references to journal articles and conference papers, the end-result being a list of citations that you would then look for in the Library. Note that many of the tactics can also be applied to any electronic database, whether it's a spreadsheet, an encyclopedia, or an online help file.
Before starting the search it is best to have a clear objective. Do you want five or ten "good" references or are you looking for as "complete" a search as possible? The procedures for both types of searches are very similar though more rigorously followed in the latter case.
Computer searches work best on very specific topics. If you are looking for a broader topic you must decide if you are looking for everything in that subject area or for general overview articles. This will affect the question you ask and the vocabulary you use in your search.
If you are starting from scratch, expect to repeat the search several times.