Choose a topic the writer knows well and understand the purpose of informational (all-about) writing: teaching the reader true facts.
Opinion writing tells what you THINK. Informational writing -- "all about" writing -- tells what you KNOW. It teaches the reader true facts about a topic.
The best topic is something you are already a little bit of an expert on: a pet, a hobby, a sport, or a place you know well. Today you just pick your topic.
Mastery looks like: They choose a specific, fact-rich topic and can explain the difference between a fact and an opinion about it.
Common stumbles: Picking a topic that is really an opinion (like a favorite flavor) instead of something with real facts to teach.