Cause and Effect
It may see obvious and easy, but the causes and effects of historical events can be very complex. Most events don't have a single cause, and the impact of events can be short term and long term. As a young historian, you need to explore these complexities and realize that every event was effected by and also affected multiple groups of people, institutions, and ideas. You should be looking for multiple causes and effects, including both those that are intended and obvious as well as the unintended and understated ones.