Go to college, and get at least a Bachelors degree. If you want to teach Elementary School, you should get a degree in Elementary Education. If you would like to teach Secondary Education, you can get a degree in Secondary Education, or a degree in your favorite subject (or the subject you want to teach). Then you would need to get certified to teach the subjects of your choice.

For college, you need Graduate Education. Community Colleges will accept professors with a masters degree, but most Universities require a Doctorate, or PhD, in the subject you will be teaching.