I suggest talking with people who work in the areas you are interested in. Some people don't care what they sell, they just like selling things ... anything .... and are good at it, but others prefer a particular area.
Some require certification. Find out what's involved.
I know several new car salespersons who make great money. An insurance agent does well also.
Do you have the skill set to be a great salesman? I know I don't.
"We cannot change the cards we are dealt, just how we play the hand." ~ Randy Pausch
"There's a difference between interest and commitment. When you're interested in doing something, you do it only when circumstance permit. When you're committed to something, you accept no excuses, only results." ~ Art Turock
"We have a saying in Tibet: If a problem can be solved, there is no use worrying about it. If it can't be solved, worrying will do no good." ~ 7 Years in T