Even though my signature says I'm an official, I also coach other sports...

1st off, it's important to have administration backing. It'll be hard, no matter what you do, if they don't have your back!

Secondly, spell your philosophy/expectations out in back & white from the get-go and hold firm to them (once again, important that admin knows these and backs these).

After doing so, if you have an issue and make an example of the first kid that fights you on this, you'll be sending a message that what you say is true and you're not playing around!

If you've already started the season, it's going to be a lot tougher, but if you establish/have established the expectations, then you should be able to still carry on with the same "example making".

Be ready for a "good athlete" with a bad attitude (and I agree with Doug - with bad/unsupportive/undermining parents) to be the first one you have to deal with. Do it anyway and it'll be worth more than gold to everyone else in the room and any future athletes!!!

They don't have to love you, but RESPECTING you is the difference maker!!!