After seeing some directions that your topic can take, you need to find your research focus. Visualize your topic as branching arrows with the different subsections of your topic flowing out from your topic. Your research focus can be one of these arrows (aspect) or a grouping of arrows (theme).
Some topics can be broken down into many individual parts and while they are all related, one part stands out to you. It can be discussed on its own and has enough resources available for your project. This can be a specific instance of your broad topic. For example, if your topic is LGBTQIA2S+ representation in media, an aspect would be a specific character.
Other topics have individual parts that are best discussed in small groups. There's an overarching theme that ties them all together. While this is more specific than the broad topic, it still has a few separate ideas. The theme approach is best used when each individual aspect of a topic does not have enough information on its own. For example, if your topic is social media influencers, a theme would be authenticity which can be broken down into self-branding, ethics, and self-image.
Now that you have a research topic, you need to find a focus. Think back on the questions you answered for the topic you choose:
The words, names, dates, places, things, etc. you found earlier are all threads that are a part of your broad topic. Search using those terms in Google, Library Search, and Google Scholar. Are you finding anything different or more specific about a certain aspect of your topic?
In Library Search, scroll down to find the Subjects listed on an Item Record. These are terms you can use to search for similar sources. They can also narrow your focus.
In Library Search, some resources have Related Reading on the right side of the Item Record. These are recommended items with similar topics or are a more specific aspect of your topic. Sometimes these Related Reading lists have what you were looking for even if it was not including in the search results.
Similar to Related Reading in Library Search, Google Scholar has a Related Articles link on most items to find similar sources.
An argument or thesis statement is best developed closer to when you begin to write your paper or create your project. At that point, you have found most of the available information on your topic and can form a solid, unchanging opinion or idea around it.
A research focus helps guide your research just as a thesis statement guides your writing but a research focus changes and evolves as you encounter new information.