Further your education whenever possible. The willingness to continually improve your understanding of the subjects you teach and of instruction methodology is what will make you an excellent teacher.
While taking courses, take care to learn as much as possible about reading, writing, math, special education curriculum, learning styles and teaching styles.
Self-confidence is important; you should at all times emit an aura of having everything under control, even when you just want to run away and cry.
Respect is earned. While you will be able to have some leverage in your position, good teaching will not take place until your students respect you.
In challenging situations (and there will be many), keep your cool; respect is easily lost.
The kids can and will try anything to throw you off balance, so have a plan to handle it before it happens.
Choose your battles; some conflicts are just not worth engaging in. It will only distract you and your students and derail the class.
Not everyone will like you. Live with it.
You will have some fantastic moments that will make you wonder how you could ever have considered anything but teaching.
Always over-prepare your lessons. Bored kids are noisy kids.
Always be prepared for the unexpected. You might have the best lesson in the world planned, but sometimes half the class is clueless to the concept and you have to adjust everything.
Be sure you know to spell and use correct grammar, Nothing looks worse than a teacher who can't spell or punctuate properly, even the students don't know the difference.
Greet your students each morning to read their moods even before the school day begins. If appropriate, hug each of them. At least give each of them each a high five and tell them you are glad that they are there. That may be the only positive contact they have all day.