Often the most neglected part of an initial analysis of any research topic is identifying the main concepts.
You should consider all possible ways of expressing the central ideas (concepts) of your topic at this stage. You will be better prepared to search a variety of databases and search tools, and ask better questions about the topic, if you develop your search vocabulary early and keep expanding and refining your list of synonyms, related terms, broader terms, and more specific terms.
Think of the following topic:
Topic: Trends and changes in Pacific development during the last 30 years.
First, let's identify the main concepts of the topic!
Look at the research question and pick out the main ideas.
Words like "trends," "changes," "effects," etc. are pretty meaningless in the scheme of most topics. Often, you will get this information (the trends, changes, and effects) by finding information on the topic anyway. So, overlook these kind of abstract terms.
As you might anticipate, identifying the main concepts of a research topic is at least as much "art" as "science". There are more likely choices than others, however. If you identified other concepts than what is mentioned above, it doesn't necessarily mean that you are "wrong".
Sometimes, depending on what database you are searching, you can ignore some of the concepts.
For a reasonable handle on your research, your topic should probably contain somewhere between 2 and 4 concepts.