Need Help with a UK Site

[marie456]

I'm working on a UK website that lives on a .com and want to optimize it for the US audience. What is the best practice for getting this site to rank better in the US, without losing it's UK rankings? Ideally I don't want to move it to a .co.uk domain since it's doing so well on the .com. However, the language on the site is localized for British English. Would I need to create subdirectory for the US pages, such as .com/us/ and then host the content that is localized to American English on those pages? Or would adding Hreflang tags suffice? Thank you in advance for the help!!!