Phew, I thought I was the only "unmannerly" person on here, haha.
I am deeply opposed to sir/ma'am.
I hate titles. My nieces call me by my first names, my nanny kid's friends call me by my first name and I will someday insist my children's friends call me by my first name.
I really think that simply living is the best way to instill manners. For instance, my nanny kid is 7. He sees me hold doors open for people all the time. A few weeks ago, he ran ahead of me and opened a door for a lady and her small child. Kids like to mimic and model. Most of them will pick up the basics. If you tell your toddler "please hand me the ball," "thank you for handing me the ball, " and so on, they'll probably get the picture. Of course there will always be kids who need a little extra help, but most will be fine.
I also really think that most "manners" are pure habit. When someone holds the door open for me, I say "thank you" out of habit. I'm not actually pondering my state of thankfulness.