We know that the United Kingdom was an enemy of the United States in the American Revolution as US was its former colony and in the War of 1812. More of like asking the developments and the gradual events that led the UK from being one of the US's enemies to a close ally.
Follow up question: is it accurate to describe the UK as the 'one of the most hated enemies' of the new United States? Was there really that much animosity between the two states? After all, a significant minority of US citizens were Loyalists and the countries shared a significant amount of commonalities, language, culture, etc.
While I can't answer, the wiki actually has a section dedicated to this topic, and two of the threads there specifically address your question.
https://www.reddit.com/r/AskHistorians/wiki/us_history#wiki_anglo-american_relations