Having a big vocabulary is a surefire way to sound smarter. If you spend your days bandying about words like "prestidigitation" "perambulation", "perspicacious" or other big words that start with p, people will think that you graduated with at least a 3.5. Maybe even a 4.0.
But the key to sounding intelligent is, if you pick an obscure enough word, you don't even have to know what it means. Because they don't know what it means either, so if you say it with enough confidence, they will believe you. For example, if you say, "Hey Mary, would you mind turning down the music? It's getting a little biblioklept in here." Sounds right enough to me. Then you can leave the party having impressed (and slightly confused) everyone there. And then when you're going to bed at night, satisfied with your performance, you can look at these memes to keep you company.