Respect. Ya. It's all about respect.
A large part of gaining that respect is making sure the players know that you are devoted to making gaming night enjoyable for everyone. Once you convince them of that, you go on to show them that you will listen to any suggestions they might make, and more importantly, that you know when you are wrong. And that when you ARE wrong, you will act to correct yourself, without worrying about losing face. If you can do it, then they know they can do it.
If all else fails, cuff them and stare them in the eyes until they tuck their tails in between their legs and break eye contact. Once you assert your position as alpha leader of the pack, they will cease to be a problem. Short command words following their names will help. I.E. 'Jim, Roll the dice!', 'Jack, Bad Prestige class, bad!' and so on and so forth.