Additionally, start off thinking about each text separately. So ask yourself "what is it about Shakespeare's work that relates to belonging, or related topics like alienation/community/identity?" And then ask yourself "what about, say, the performances of Firth and Rush? How do those convey a sense of belonging or lack thereof?"
Only once you've cultivated a deep understanding of each text on its own merits should you start to consider commonalities or differences.
Instead of thinking of belonging as a quantity ("heaps of"), think of it as a recurring motif - and then try to understand where and why it pops up in different parts of The King's Speech. For example, you might want to focus on the relationship that forms between George and Lionel - from the very rapid development in the first few scenes to how it morphs, takes damage, and grows stronger through the film. That's how you treat belonging as a discrete feeling, instead of a general "thing" in the text.