PA, Social Justice, make me time.
5 Things Smart People Shouldn't Say. There's a lot you can change about your presentation to make yourself seem smarter (and, hey, if you want to go for substance over style, plenty of ways to actually be smarter), but few have a bigger impact than eliminating bad speech habits.
You're an educated person, however, who knows to stay away from "ain't," avoids the valley girl staple "like," and steers clear of fillers like "ummm. " Does that mean your speech is as polished as it could be? Chances are that no matter how clever and careful you are, you're still making at least a few inadvertent errors that lower others' opinion of your intelligence.