First, get relevant information from the direct source of the event/incident. Wherever the news comes from, try to get in touch with the actual source as this is how you can get accurate news. For example, if you are writing a news brief on a seminar, contact the organisers to get accurate information/press release. You may be away from the source and in this case it is usually hard to make direct contact but you can get the news from a second source (which can be independently verified).
Cover these key questions when you start crafting the brief: What, when, where, who and how. These key questions are enough to let the reader know what the news is all about. Since news briefs are usually short and precise, just sticking to these questions can make a good story for the newspaper.
Give a bit of a background on the event/incident. It is good to add some details to a news brief as it will make the story more comprehensive and give the readers full understanding of the event/incident.
You may be required to follow up on the news brief you have just written or are going to write. In that case, ask your source for the permission to do the follow-up on the news. Most of the time, the source will voluntarily get in touch with you and brief you about the follow-up. For instance, a crime story may last for a few days to a couple of months. In this case, you will have to keep in touch with the sources such as people involved in the incident, police, law enforcers, court, etc.
Write the news brief in plain English. Make sure that the language you use is not full of adjectives, as it kills the purpose of the news. Double-check the facts and remove irrelevant lines.