Hi,
Hope you are well.
I go two or three time a year in the US. I am a European citizen .I do the Esta first from their website.Then I plan my trips . Most questions they ask me when i cross the border:What is the purpose of my trip , how long i intend to stay , where do I stay, how much money i have during my trip. What kind of job i am
doing in London ? They never ask me to prove my job , only one time i was asked the name of the company and name of my manager but not sure he tooke a note of it. I work part time employee and also being a self employed. So only mentioned my part time job.
Hope that help.keep a copy of your hotel room booking and plane
ticket , that can help to prove your saying .