The definition of "Regular Joe" is a synonym for the more common phrase, "Average Joe." Which means, obviously, an average, ordinary, everyday, normal person. All politicians were normal people before becoming politicians. All you have to do to get into politics is start from scratch to small positions. For example, while you are young, you can run for student council at your school. From that you have a stronger background in politics, and once you are older, you can run for city council. From city council, you can go on to state representative and have a place in congress. Once you're in congress, you just have to make yourself well-known by performing well and being a likeable person. That is when you can run for senate. Once you are "tired" of being in the senate, you can go two ways:
1. The way with the lesser probability of presidential election. This path means you go from senate-president. Which doesn't happen all that often.
2. The way with the greater probability of presidential election. This path means you go from senator-governor-president. This way happens very often, and even though it takes longer, it is ideal.
I know I have gone on a lot with this opinion, but as you can see, any average joe can become a politician. All presidents, vice presidents, senators--you name it; were once regular joes.
The current president is a very rich regular Joe from Queens NY. He doesn't read books and could care less about intellectual persuits. He likes Twitter and Facebook and chasing pretty girls. We are now seeing in real time what an average Joe president looks like. There are plenty of average Joe's with lots of money. Trump would have been president regardless of the money because America wanted to elect an average Joe loudmouth type.
It is completely possibly to rise the ranks even into national politics. The process is always longer if you do not have a college degree. But experience and wisdom will prevail and speak louder than any piece of paper.
As others have said, you will have to gain experience in dealing with people. Have a likable personality, know the issues, be passionate, have a mix of philosophy and science.
In order to become even a blip on the radar of the political monstrosity that we call our government you need to have funds far beyond what the "Average Joe" could ever imagine. I can't even begin to fathom how individuals can't see how unjust and unfair the system is when you are not apart of the upper class. With money you can attend an elite university, make friends with influential business owners, buy elections and cover-up any dirt from your past. The "Average Joe" would never be able to accomplish all of these things without money.
Simply economics prevents anyone regular person from becoming a national politician. You need to be able to afford to go to the finest college in order to build your resume. It usually helps if you serve a tour in the military. The military pays little in the way of trying to build a war chest. So when you are in debt over your head from school and a small salary, you cannot compete with the rich in regards to politics.