When starting to do research you need to know what you are looking for. After you have a topic idea, you need to make a list of keywords for searching. One very good way to increase your searching vocabulary is to add Synonyms and Antonyms for your keywords. Very often a term you are searching for can be dated, regional, or more slang than technical. By making a list of all of the possibilities, your searching can be more successful.
Take for example an iPhone: it may also be referred to as a smartphone or a cell phone. Less commonly, it may be referred to as a mobile phone (or a mobile); in early days cell phones were also called "wireless phones" or "car phones". It can also be considered a telephone or a phone (phones once were called landlines and were hard wired into a house). This example can help you think about how to find additional searching vocabulary.
Some databases, such as Academic Search Complete, use something called predictive text or predictive typing which will offer you suggestions. For example, when you type "college" into the search box, it offers you "college OR university OR higher education". This automatically offers you synonyms for college, joined by the Boolean connector OR [note, the OR is not in capital letters in databases, this is just for emphasis].