A reasonable starting point for many research papers is a basic web search. If your topic is elephant poaching, for example, you could do a search for elephant poaching or perhaps elephant poaching blog or elephant poaching news.
Newspaper articles tend to be fairly short, but they also often provide real-world examples and quotes.
Blogs can be written by either individuals or organizations, and some blogs are informative and reliable. They tend to be relatively detailed. If you are concerned about reliability, take a look at Evaluating Sources.
Here are some websites for finding academic papers in professional journals. As a high school student, keep an eye on the difficulty of these sources. Professional research papers are written for professional audiences — not high school students — so sometimes they are difficult or impossible to understand. When you’re trying to decipher something challenging, spend a few minutes on it, and if you don’t make any progress, either ask for help or find another source.
Keio Database NAVI – useful for Keio students
The above sites work much better with a subscription. Your campus probably has a subscription, so try to do research on campus. Or, try a public library; many public libraries have journal subscriptions.