The easiest way��at least in terms of getting a visa��is to apply for and be accepted at a U.S. university or college. Once you are here, it will be much easier to find employment��one who might eventually want to help get a permanent visa.
From the UK, it s difficult. There is a quota for work permits and supposedly a long waiting period. You would need to have an employer here who is willing to help with your paperwork. And in order to get a job, you would need some specific skill or work experience that is not easily found in the US already. If you work for a company in the UK that has branches or offices in the US, you may be able to be transferred.