As you have noted each state in USA has different requirements. The general requirement are as follows:
- Obtain a Bachelors in Engineering (BSE) from an ABET accredited engineering program. The disciplines that I am familiar are Electrical, Civil, and Mechanical. I suggest you review the references below of more detailed infomation.
- Successfully complete the Fundamentals in Engineering exam to obtain Engineering in Training (EIT) status
- Gain professional experience (typically four years minimum)
- Learn about California state's licensure requirements
- Successfully complete the Professional Engineer exam