One thing I'd encourage for new players is to try to get them to think like their character, speak and act (figuratively speaking) like they would rather than just playing themselves. It helps if you have premade characters with some fleshed-out background details, and can be a little more difficult if the players are generating characters at the table. At least 5e's backgrounds help out this process quite a bit.
Make sure that everyone's aware it's a cooperative game, and working together will be more fruitful than going alone. Remind them that you're just the messenger, not the enemy.
As others have mentioned, find out if they're fans of fantasy movies, tv series, anime, video games, or comic books. I find that often I can give players a better mental picture of an NPC if I tie their description to that of character from other media. They're also more likely to remember them.