Research, research, research. The more you know about the event and its context the more likely you will be able to report it accurately. Rejecting false information is equally as important as accepting the true. Cross check sources and try to locate as many as possible. If possible use first hand sources, eg spoken testimony, transcripts, interviews, documents, images, video. Go to the sources themselves. Note that many news reports are based on other media reports or news agency reports such as Reuters or Associated Press. Use agency reports rather than rewrites of them.