Speak clearly and slowly, repeat important points, and write anything your students should remember on the board. However, it is important to give students a sample of what they can expect. Introduce the subject, conduct a simple experiment or hold a casual discussion related to the course material. Students need to become familiar with how you will conduct class, your voice and your expectations. The first class can set the tone for the entire semester.
Enthusiasm is often the best teaching technique.
If you enjoy and respect the material, your students will also. Look through your students index cards or your attendance notes. Talk To Your Peers. Share your experiences. Now that you have made it through the first day of class, celebrate.