Okay, below is a rough rundown of the most common ways people emigrate to the US (Most of this is from memory so apologies in advance if I get the names of some visas incorrect):
CR-1 (Marriage Visa) – By far the “quickest” and “easiest type” of Visa to obtain, all you need to do is convince an American man or woman to marry you, simple, once obtained you can get a green card and work in any old job that will take you!
L1 (Company Transfer) – Probably the second “easiest” visa to obtain, work for a multinational company in the UK and get a transfer to the US, though you will need to have a fairly significant role within said company, don’t go running for a checkout job in Asda thinking you can get a transfer to Walmart.
H1-B (Temporary worker of distinguished merit and ability) – I assume this is the Visa the OP is looking at, emphasis on the distinguished merit and ability, I think the US issues around 65,000 of these a year, and they receive 300,000+ applications, essentially you need to be able to do a job that no US citizen can do.
There’s also investment/business based visa’s but these require investement of around £500k-£1m I think, and to employ a certain number of US nationals e.t.c.