Not doing research. You think you already know, so you don’t do necessary research. You don’t question. You fail to ask yourself if what you wrote is really true. In the first draft of the second book of my series, I had the characters standing on their heads in a turned-over space craft, and the universe was divided into quadrants. One of my Beta readers said, “There’s no right side up in space. And where did quadrants come from, Star Trek?” I’m glad she called those errors to my attention, as such mistakes can damage a writer’s credibility.
Using only one website or source. Wikipedia is a place to start, but have you ever noticed the number of  places in their articles? Their website is put together and updated by people who think they know, and people make mistakes. Even if you’re using only internet sources for your research, check out several.
Not using your public library. Using a library is free. Go in and browse books on your topic. Read another author’s opinions. Seeing photographs in books is not quite as good as being there, but it helps. If you can’t find what you need, ask for help. Don’t forget that libraries have much more than books, magazines, and newspapers. The librarian will know about resources that you may not have heard of.
Being too shy or afraid to ask for interviews. Most people love to talk about what they do and tell about their experiences. Talking to experts in their field is a great way to pick up trade jargon and get a feeling for their work. Perhaps the information you gain will open new plot possibilities or suggest an idea for an interesting twist.
For us writers who have an undying sense of curiosity, doing research should be fun. Make it worthwhile by avoiding the above pitfalls. Donna Wittlif