The primary ingredient in a science fiction story is the science. As these stories usually take place in the far future the science you postulate can be problematical, but must be reasonably possible as well. If it is not, the educated reader will not suspend disbelief.
As most writers are not science majors this means a much difficult research into a large group of subjects, each having its own lexicon. Therefore, the first research tool the science fiction writer needs is a good lexicon dictionary such as "Chamber's Technical Dictionary", the "Dictionary of Scientific Terms", or the "Aerospace Age Dictionary". Using these books you convert the lexicon into everyday English in your notes.
In doing story research you will find basically four research sources: public records (i.e. government study reports), books, periodicals (magazines and newspapers), and interviews. Before interviewing any experts in your research field discover all you can from written sources. If you don't you will not know the best questions to ask.
It often happens that when you are gathering data you find your authorities do not agree on facts or interpretations. Sometimes you can determine the dependability of your conflicting data by the dates. A recent scientific publication is more likely to be accurate than one written even ten years ago. Also, professional textbooks are more dependable than your average "coffee table book".
If you are beginning research into a totally new area those "coffee table books" can give you a general feel for the subject. A better way to begin learning a new discipline is to check your library or bookstore children's section. These books are generally more in-depth than "coffee table books", and assume less technical knowledge on the reader's part.
Most people think science is cut and dried. That is not always the case. There are many gray areas. Even between respected authorities there are often different interpretations from the same data.
One such on-going argument is whether the dinosaurs were cold-blooded or warm-blooded. Another is the cause of their extinction. Some theorists say it happened because a comet or asteroid hit the earth. Others say a sudden ice age occurred, caused by a variety of reasons ranging from a neighboring star going supernova, to the earth being tilted by a companion dark star passing near-by. Still others claim small egg eating mammals did the dinosaurs in. The theories range from the possible to the silly.
To help yourself evaluate the reliability of your material you ask yourself three questions:
You cannot always go by the publication date in answering this question. A new publication may well propound an outdated or biased theme, such as those put out by special interest groups who do not want to accept reality. As an extreme example, if you research astronomy it would not be helpful to get your data from a book written by those who insist the earth is flat, and is the center of the universe.
If the data you require concern past events and beliefs, a journal or diary from that time is likely more accurate than a new publication.
Whatever the facts you are unearthing, always try to corroborate them from at least three separate sources. Three different books written by the same person or group is not going to give you a cross-check.
Check to see if the data is supported by evidence, or is only the author's conjecture.
Even official versions are not always correct. It is bad scientific procedure to doctor the results, but it does sometimes happen. Authorities occasionally leave out inconvenient data which conflict with their expectations, or will falsify proofs to support their own interests.
Nova pointed out a prime example in reviewing fossil hunter Othiel Marsh's activities. In 1879 he located a brontosaur skeleton minus the head. Finding a skull without a body 400 miles away, he added it to the brontosaur. This fake was used as a model for subsequent restorations for fifty years. At that time another brontosaur skeleton was found intact.
Also, scientists are human beings. Human beings can make honest mistakes. The much joked about German scientist Tornier, a Berlin expert on dinosaurs in the early 1900's is one such. According to Robert T. Bakker, Ph.D. in his book "The Dinosaur Heresies", Tornier insisted that the legs of the dinosaur Diplodocus protruded to the side like a modern reptile, not straight up and down as in an elephant. In the United States, Carnegie Museum's Professor Holland joked that the German Diplodocus "would have had to find giant ruts to run in because its rib cage was so deep." By 1920 the "Great Trans-Atlantic War" over Diplodocus posture ended. "The Americans clearly had the better of it."
Assuming your science fiction story takes place in a star traveling society, one major subject you need to research is possible stars for life-bearing planets. In part two I will go into star shopping.