What's the best way to get my squad to listen to me when I provide guidance and direction?

Treat them like your brothers, not your friends. You can be friends, but there needs to be a professional line as well.
But mostly, be someone they respect and look up to, and they'll follow you. As Sun Tzu said, "treat your men like your trusted sons and they will follow you into the darkest Valley".

Some old saws for your kit.

Be fair. Be firm. Be resolute. Be responsible. Be respectable.

Demand a lot from them, but more of yourself.

They're watching... Every time you cut a corner, pencil whip a task, "just get by" or act the ass; you just showed them what is OK.

Finally.... what gets well-inspected, gets well done.

Well if you grew up with these squad members they may have a problem seeing you as the squad leader and you will need to be all bossy. No matter what you do, if you are going to be successful in the same squad you will been to be all bossy until they get that your the guy responsible for the actions. I was in the same situation when I got my first Bn scout squad in the 82nd. E4 squad leader. As a team leader you all still had a boss to take the flak but now that guy is you and the buck stops with you. If you are doing a good job you will hear comments like, those stripes have gone to his head, he’s a jerk with those stripes, and worse. That what being a boss is about. Being responsible. You don’t have to be a jerk but you have to make them do what has to be done. If you don’t and you act like your one of the boys they will run over you and your PL will look for someone willing to do the work.