Difficulty: Moderately Easy
Step1
Recognize what you do know about the topic and find a way to package and present it more intelligently.
EXAMPLE:
Before: "Geometry is about shapes."
After: "Geometry encompasses recognizing and identifying patterns in shapes and using these inferences in structural design, which can have multiple implications."
See how much smarter that sounded?
Step2
Ask a lot of questions to the person who sounds like they know more than you. Chances are you can catch them on something they don't know, or something that contradicts something they previously said. Once they do slip up, you respond with "Yeah, I knew something sounded wrong there."
Step3
If you realize that you are conversing with a crowd that won't know any better, simply make up your own information, just make sure it sounds realistic and informative. Chances are, you won't be cross-referenced.
Step4
Occasionally, toss in a reference like a study conducted or a quote by a scientist (or just the name of a scientist will work).
EXAMPLE: "Did you know that 47% (the more random the number, the better) of male Silverback gorillas are born completely sterile? The find was confirmed by Jane Goodall's work, but had been hypothesized long before her study was completed."