I loved the Star Wars movies, and one of my favorite characters was Yoda. Yoda was the spirit guide who dispensed wisdom to young Luke.
"There is no try," said Yoda, "There is only do." Don't just "try" to do things, commit to doing them the way that you promise.
Then, hold the folks who work for you to the same standard. Here's a variation on Yoda's advice. It should help you supervise more effectively.
There is also no be. There is only do. You can't change people. The only thing that you can manage is their behavior (what they do), and the only thing that you can control is your own behavior (what you do).
Instead of concentrating on "motivating" the folks who work for you or fixing their "bad attitude," concentrate on setting standards by what you say and do, on doing lots of supervisory interviews, and delivering the promised consequences of your subordinate's behavior.
There is no try. There is no be. There is only do. And it's up to you.