Once you have decided to look into the idea of studying in America, your first port of call should be the Fulbright Commission. Its website is the best resource for applying from the UK

 Do your homework: You will be spoilt for choice. There are 4,500 universities ranging from small private liberal arts colleges that concentrate on teaching to large public research universities with enormous student bodies. There is no limit to the number you can apply to but it is best to limit your choice to six or so. You may find it useful to attend Fulbright’s annual “USA College Day” held in London in September where you can talk to admissions staff and alumni from 150 American universities.