From the Picking Your Topic video above you know that: "...picking your topic is intertwined with reading your information sources." The research process is not linear. Learning about your topic forms and transforms your topic.
Get acquainted with your topic. Think of it like going on a date: you're trying to get to know the other person (your topic) without scaring them off because you're trying to talk about marriage, houses, and grandkids (i.e. your "real" research) on the first date. And, of course, once you've gotten to know them better, you're able to buy them gifts and guess what they would like, because you've taken the time to establish those little basic details. The benefits of getting to know the topic are explained further in the next section.
Your textbook is helpful at this stage, for starters.
Honestly? This is the time resources that are otherwise verboten are useful. You know... Wikipedia, Shmoop, or even just whatever comes up when you Google for your topic. These are not the sources you're going to cite in the end -- you just need them to give you ideas in a simple and straightforward way.
If you want an option like Wikipedia but better, check out Credo Reference (linked below). It provides short synopsis articles from reputable encyclopedias, and even has a mind map tool to help you visualize how topics relate to each other.
Start off with your overall central topic: in this example, we're starting with Game of Thrones. What can you think of about that show? It's in the fantasy genre, it's adapted from a book series, it had a huge cast, it won awards, people liked (except when they didn't), it had highly-quality set design (except when it didn't)... and on and on.
You're trying to accumulate lots of ideas at this point! Big picture. Make connections, and write whatever comes to mind. When you start getting stuck, turn to Google, Credo Reference, and/or Wikipedia to get more ideas.
Once you've filled out the map of your topic a bit, look at where you have the most ideas: this is probably the strongest aspect of your topic, and what you should focus your research on.
All those other ideas? We're not going to use them. We want to deeply explore one narrow aspect of the big topic, not try to talk about everything to do with the big topic ever. (That's the job of probably a multi-volume book, not a short essay!)
It's important to still go through this process, though, even if we aren't using most of the ideas, because a) we have to see all this to figure out which thing we're targeting, and b) it still gives us context for how we actually understand the overall topic -- everything is connected! Plus, if we decide we hate our chosen topic, we can come back to drawing board and go another direction easily.
This end result of our mind map is the research topic we'd look into further for the paper: how the costumes were designed for the show and how they were used to reinforce aspects of the fictional cultures displayed. Now we can start targeting our research to just those aspects, either for the show in particular (probably web and news articles), but also more general resources about costume design that we can apply to what we've seen here.