Competence follows desire.
Your primary task is to motivate children to learn something, because once they are motivated, learning will naturally follow. 

Positive feedback, even when unjustified. It's a self-fulfilling prophesy.
Thou shalt not judge, belittle or discourage.
Thou shalt not criticize without following with some constructive encouragement. 

Trust, treat with respect, and treat like capable adults. It's a self-fulfilling prophesy.
Do not belittle or ridicule them.
Don't bite the hand that feeds you, bite the hand that slaps you. 

Curiosity is holy, and you shall encourage all forms of it.
Any intrigue, question, wonder or even distraction holds value, and deserves and demands room.

Be humble and improve.
You are never as good as you could be. Given your position of huge influence, power and responsibility, our world demands greatness from you. Evaluate closely, and always seek to outperform yourself of yesterday. 
If kids are not engaged with your lessons, it is your job to improve that. Nobody but you is responsible for teaching the kids. Their instincts to boredom are not incorrect, and are not their or their parents fault. And even if they are, they are your problem to solve. So take their revolt as your own underperformance, study carefully your shortcomings, and improve. Ask yourself this: does there exist a person in this would that would be capable of engaging these kids? The answer is yes. Imagine what that person would do to achieve the impossible. Or better yet, ask! Some teachers and public speakers can be very engaging. Do not resent them with jealously or make excuses. Be pragmatic, wise and ego-less, and copy their best ideas. If they can do it, you can too. They are not magic. They'll be happy to help you along.
The most courageous thing you'll ever say is help. 

Tolerate and encourage criticism.
If you believe and preach critical thinking is important, and you value others in your society to be able to think critically, then support this behavior in class. Do not fight by means of authority. Argue by argument, and respect their judgements.

Respect non-conformists.
Those who reject authority in favor of their inner clock, are more likely to start successful organizations than those who obey. Do not resent or discourage it. Admire the independence and self-trusting judgement, and nurture it to be applied constructively and beneficially.
No great advance was made by following the status quo and conforming to instruction. All innovative things you enjoy in life were invented, created and fought for my free-thinking rebels. The abolishment of slavery and segregation, women's rights, employee labor rights, the abolishment of corrupt monarchies and dictatorships, the invention of the blue LED, the invention of the airplane.
The rejection of authority is a fundamental principle of advancement. Cherish it. 

Do not motivate by threat of failure or punishment.
Learning is not punishment, and should not be presented as such. And the sole motivation for kids to listen in class, do exercises and learn well, should not be to avoid punishment. 

Build adults you can trust your future on.
Your future relies on them. They will work, vote and purchase from the companies, governments and institutes that you will come to rely on as you age. Would you like a nice life later on? Then educate them in such a way that will help them create the best environment for you, and each other. 

Don't exam.

Don't

Just don't

yeah I still have to work on this part :)