1. Don't worry! The best way to learn is by doing. Adopt a scientific approach, keep your lesson plans and figure out what works and what doesn't. Ask yourself that question after each lesson as you're starting out: What worked? What didn't? Why? Things will get easier as you learn about the local culture and your students' personalities. Everybody's first few months are hard.
2. Use common sense and assign tasks in order of increasing complexity and personalization (matching, gap-fills, sentences, then something in their own words).
3. Make sure to emphasize the useful aspects of language and those that relate to your students' lives.
4. If you have fun, your students will, too, and they'll learn more if they're having fun -- games are sometimes the best ways to teach and to learn.
5. With little kids, a little reward goes a long way. Consider establishing a points system with rewards for good behavior and loss of points for bad behavior.
6. Put students in groups and let them police each other -- that will make your life a lot easier.
7. Remember that every lesson should be student-centered, with a focus on mixing up patterns of interaction.
8. If you're talking much, you're talking too much.
9. Instead of thinking of yourself as a lecturer (as many people do), think of yourself as a coach. While your students are working together, walk around and coach them individually. You'll make more of an impact talking to students as individuals.
10. Sometimes students will ask awkward questions about grammar and usage that are too complicated to quickly explain, or about matters that have already been covered and re-covered in class. Don't be afraid to tell them, "We don't have time to talk about that right now, but I'll explain it to you in just a minute/after class/next semester."