One very common issue - or concern - for International SEO is duplicate content.
Can you simply copy over your pages (and strategic content!) to a new international site or folder (see: parts of a URL), stick some hreflang tags on there, and call it a day?
The short answer: nope. Not if you want it to, you know... work.
One caveat: if the content is translated into a new language (multilingual), you don't have to worry. Ideally, you are doing good translocation work to make these pages great, obviously, but don't worry about duplicate content for a page in Spanish that you've translated into German. More about multilingualism vs. internationalization below.
Here's what typically happens: you've got an English-language site targeting the US, and you want to go after the UK or Canadian market (or you are in French-Canada and want to target France, etc.) The executive team wants it done quickly and cheaply with little to no additional marketing spend (... am I allowed to LOL at this a little?) so the engineering team copies the site, puts up that copy on brand.co.uk or brand.ca/france/.
The SEO team freaks out a little and - given the budget issue - engineering deploys hreflang tags, and maybe an international XML sitemap.
Then, 2-4 months later, the executive team is wondering why none of the new international pages are ranking - or why the Canadian version of that URL is ranking in France instead of the French version.
There is more work to be done. But how exactly do we do that?
How you resolve this issue comes down to your business' goals, budget, and resources - i.e. what is easiest and most economical for your team to execute.
Always do your keyword research to understand what's searched, where, at what frequency - this can lead to unique content you can target for different audiences.
There are any number of additional editorial angles - but hopefully, this list is long enough to get your wheels turning. So dig in, get started, and don't be afraid to try things and make mistakes. Some will work, and some won't. You'll fix those that don't as a part of your normal, ongoing content auditing process.
If you have other questions related to International SEO, please reach out!
Multilingual only, not international: a brand in Belgium - only - with Dutch, French, and German language pages (target language: many, target countries: 1)
Multilingual AND international: a brand in Germany with German & French & Dutch which is also targeting Germans-speakers in Belgium, and French-speakers in France (target language: many, target country: many)
International only, not multilingual: a brand in the US with only English-language targeting Canada and the UK (target language: 1, target country: many)
There is certainly "gray area" depending on the language itself. Written British English vs. American English is not substantially different - there are some added/missing "u"s here and there (e.g. colour vs. color) and some differences in "slang", but not so great that it's not easy to understand one another. Spain Spanish vs. Mexican Spanish is more substantially different, for example, so may have less duplicate content issues.
A very simple rule of thumb for determining duplicate content: will a duplicate content checking tool (e.g. Quetext) flag it as duplicate? If so... it's duplicate!