Decide what you want to know.
This is key as to where you want to research. If it is of general nature, I suggest looking at children’s books because they are written very tight and to the point. Children’s books are great source for research when you really aren’t sure what you are looking for but need a good overview of a topic, event or period. Once you have a good overview of your topic, then you can do more detail. Be aware this simple beginning research might take you in a different direction
Find out what has been done already.
Look at the research you have already done for other books or projects. You may have a source in your notes already. For every source you use even if it doesn’t pan out make a note card of it documenting the source tp keep for future reference. You never know but you may already have the answer in your questions either for a writing or family history. The key is to document ever source: title, date, author, page numbers and if you don't have the book or record document where you found the book: library or archives.
Break down your search for information.
When researching broad topics or a broad family surname think of a few general themes or topics: people, events, locations, economic, and cultural elements/event. When you researching a broad topic then keep notes by sub-topics and then keep them in a folder or file under the broader topic or family.. Then research each topic looking to create sub-topics in each for future use. You never know what you will need later. Always keep a bibliography of research books, libraries, archives and historical societies you have used for each project.
Make a list of books, places, people, and historical/events important to your project.
After you do a basic search for an overview make a list of people, places and events. If it is an historical look for both political and social events and if a contemporary you still need to know the current events of the location and time. All these add realism, to your story so do your research and to do that your need a systematic way of finding, recording and storing in in way you have access to it.
Estimate how long your search will take.
The problem with research is it can take time. If you are researching a minute detail at some point when you can’t get the answer in your search you have to step back ask yourself how important it is to the story at hand? Although I would love to say that this doesn't apply to family historiasn but we too sometime have to step back and admit that the record with the information may no longer or never did exisit. If it is important they you have to decide when you are going to stop and get help from more experienced researchers or genealogists.
Identify and contact possible sources of help?
There are many fellow writers or family historians who are willing to help you. Don't be afraid to contact those writing in the same period/location or for the family historians those who are researching the same family surname or location as you. You have many resources in your community including your local library's resource librarian. If you are a near a university many encourage the use by locals and provide access to check out books. Most local communities both here and abroad have local historical socieites or historians. Seek them out for not only for the history or answers to your questions but they are a font of infromation on sources found locally. These are great resouces for both family historians and for authors.
Conduct primary source research.
Primary sources are the most basic research tool because the record usually was written in the period in which you are researching and is usually closest to the event or period in question. Primary sources are key to research but to find then you have to use secondary (secondhand accounts usually offering an anaylsis of the event or person different because of more information ) and tertiary (an index or source that consoldates both secondary/primary sources on topic). As always remember to cite all of your sources to add to your research notes. These will be useful if you have readers (authors) or other family historiand who question your information. .