It's nice to think that the reason that people don't do what you need them to do, or conform to your standards, or make good choices is simply that they don't know enough.
After all, if that's the case, all you'll need to do is inform them, loudly and clearly.
So, that employee who shows up late: just let her know that being late isn't allowed. Threaten to fire her. That'll do it.
The thing is, ignorance is rarely the problem.
The challenge is that people don't always care about what you care about. And the reason they don't care isn't that they don't know what you know.
The reason is that they don't believe what you believe.
The challenge, then, isn't to inform them. It's to engage and teach and communicate in a way that shares emotion and values and beliefs.