Primary Research is information obtained directly from people, places, or events. This type of research is valuable because it draws you in and makes you, the author, personally involved. It is usually obtained orally. When I wrote a story about a jade theft in Taiwan, I went to my local jewelry mart and asked about the different colors, prices, and qualities of jade. They were happy to answer my questions.
People are wonderful resources, and they are usually willing to help an author. Call scientists, policemen, doctors, college professors—experts in whatever field you are writing about. Once when I was talking about a bullet, I had written 32 caliber, and my police detective friend said I might want to change it to .32, or it would be a very large bullet!
Go to your locations, and walk where you have your main character walk. Talk to people who have been through a similar experience. Find as many sources as time permits. Once you have been there, the setting will come alive for you. Then use all your senses to paint the scene for the reader. A word of warning: If you are painting a real scene, make sure you have been there recently. Things may have changed, and you want them to be accurate.