The first thing you need to do is clarify your topic. What is your research or paper about? What should and should not be included? In addition to determining your topic, you also need to think of search terms that will provide you with sufficient sources that fit your topic. Make sure that your search terms match the commonly used terms in the relevant research field: how is your topic written about in literature? Which terms and words are used? Adjust your search terms based on what you find. Sometimes you might come across other terms in an article that fit in well with your topic, which you also include in your further search strategy. For example, the term ‘tight oil’ regularly crops up in research into shale gas and shale oil. It would therefore be wise to include this term in your search. English-language websites often provide more and better search terms (for example, the English version of Wikipedia).
When creating your list of search terms you can also use different types of terms:

• synonyms (words with the same meaning)
• broader and narrower terms
• related terms
• antonyms (words with the opposite meaning)
• translations in relevant languages
• individuals and organisations that are important to your topic
• also think about different forms of words (singular, plural), spelling variations and possible abbreviations.

There are also a number of tools that can help you come up with your list of search terms. Words from sources that you have already found, from textbooks, from a background article on the internet (Wikipedia, for example) or from dictionaries or thesauri can help you on your way.

In academic literature you will find different information than in policy reports. Therefore, you need to work out in advance what information you need and what you need to get from that information. Example: you discuss your motivation for a topic based on something you saw or read in the media; the theoretical exploration and definition is based on academic literature; you discuss the context of your research field based on policy reports and statistical data. Identify the information you are looking for and in which documents you think you can find it. That is how you do a targeted search.

Once you have an overview of what you are looking for and in what type of document you will find it, the question is where to find that document. There is no single general search system so you will have to use different databases. The database you decide to use also depends on the type of information you are looking for. If you are looking for information about recent developments, you will be better off using academic articles than books. However, a handbook is exactly what you will need (e.g. Daniels et al., 2009) if you are interested in a well-known theory (e.g. Wallerstein’s ‘world-systems theory’) or a general geographical topic (e.g. gentrification). On the University Library website, you will find an overview of the search systems for each field of study, as well as short descriptions. You will also find the LibGuides. These ‘guides’ provide more information about using the various search systems. Familiarise yourself with these tools; being able to work your way around these databases is essential for finding the right and relevant information.

In our field, Scopus and Google Scholar are popular tools for finding academic articles. When looking for books, you can use the University Library catalogue (for books that the library has, both in paper and electronic form) and Google Books for finding information about books, such as the title, author/authors, or table of contents.

Now you have your search terms, you can start searching. Two things are important here: 1) how do you enter search terms? and 2) how do you develop your search in a systematic way?
The way you enter search terms influences the output. For example, if you use multiple search terms at the same time in a search, almost all search engines search for documents that contain all the terms you have mentioned. You can make your search even more specific by using operators:

• By adding AND, you can search for a combination of terms. For example, “climate change” AND adaptation.
• Whenever you add OR, at least one of the terms must be included in the results. For example, citizenship OR citizen participation.
• By adding NOT, you can make the search more specific. If you want to find information about crickets (the insect), you should formulate your search like this: cricket NOT sports.
• If you have a search term that consists of several words, or words that have to be written in a specific order, use “…”. For example “citizen participation”.
• By placing an asterisk * after a word stem, you search for all possible endings of that word. For example, use govern* to search for government, governing, governance, governed, etc. in one go.
• You can also use filters and limits to find only the information that is relevant to your topic. For example: sources from 1990 onwards, or as subject area, limit the information to the Social Sciences (and do not include other sciences).

There are several ways for you to develop your search in a systematic way. You can start with a very broad and general search and then focus in on your topic later on. This can help you get a general overview of your topic quite quickly. When doing research on world cities, for example, it is a good idea to first get an idea of what world cities are, what we understand them to be and what has been written about them in general. But be careful that you do not get bogged down in general literature; at some point you should start to really focus your search strategy. What aspect of these world cities are you going to research? What will you focus on?

The results of your search are, of course, also important: do you have a lot of results and can you no longer see the wood for the trees? Then you need to use more terms and more specific terms, filters (for example, search by year) and use AND instead of OR to define your topic. You might find yourself in the opposite situation; if you get too few results, you have to use fewer and broader terms and you should use OR instead of AND.

In the snowball method, you start with documents that you already know. You conduct your search based on elements in literature that you have already found, such as author, references, keywords and citations. Please note: by using this method you will only find literature that is older than the document you started with. You also run the risk of mainly finding literature that is written from one way of thinking or perspective. To find more recent literature, you can search for citations in search engines. Various search engines show which authors have subsequently cited the found document in their work. This literature is often relevant to your topic as well. You can also use a number of search engines as a starting point and systematically work through your list: search for the terms you have compiled using all the search engines and compare the results.