The most important thing to have as you start the research process is wonder - an attitude of curiosity and interest that makes you ask questions and desire answers. If you are given free rein to pick your research topic and don't know where to start, think about what you are curious about or what interests you - try making a list of topics, starting broad, and then start to narrow it down into something more specific.
E.g.: British literature - the novels of Jane Austen - Pride and Prejudice - the characters of Pride and Prejudice - Elizabeth Bennet
E.g.: aviation - history of aviation - aviation in WWII - developments in aviation technology in WWII - use of radar in air warfare in WWII
Gradually, you want to whittle your topic down until it is focused on something particular. Then, to help refine your research interest even more, it is time to work your focused topic into a question - think about the who, what, when, where, why, and how of your topic, or ask about the history, the structure, the comparisons, the problems, the categorization, the what ifs, and the arguments of your topic.
E.g.: Who is Elizabeth Bennet and why is her characterization in Pride and Prejudice still appealing to modern readers?
E.g.: How is Elizabeth Bennet different or similar to heroine characters of other novels written at the same time as Pride and Prejudice?
E.g.: What is radar and how did its development affect the strategies of Allied air forces during World War II?
E.g.: What if radar had not existed - how might the outcome of German air raids in Great Britain, known as the Blitz, been different?
Now, a good research topic doesn't stop with just a good question - it makes a claim which provide a possible answer, then argues and supports that claim with evidence and trustworthy information. If you are not already familiar enough with your topic to have an answer to offer or claim to make, you may have to some searching and reading in your topic to get some ideas first. Don't be frustrated if you have to go back and forth, adjusting your research topic as you learn more - it's all part of the process (you just need to give yourself enough time to explore)!
In the end, you want to have your research topic spelled out in a single sentence which summarizes your specific claim and the main ideas you are using to support that claim - this is called a thesis statement. You can tweak your thesis statement as you continue your research also, and once you're finally ready to write, use your thesis to help you organize your paper.
E.g.: Elizabeth Bennet, the heroine of Jane Austen's novel Pride and Prejudice, still appeals to modern readers because she is a strong female lead, which is characterized through her resistance to societal expectations for a single woman in the 18th century.
E.g.: The development of radar technology during World War II was integral to the ultimate victory of the Allied Forces, as it newly allowed them to detect incoming aircraft and direct anti-air defenses, as well as attack targets at night and during inclement weather.