Thank you for reaching out today, and this is a great question. Shipping internationally is one of the biggest headaches to deal with when scaling your business, and it can prove difficult making it profitable. Hopefully there are some members here who can share their own experiences with you but I have a few pieces of advice I can share.
First of all, I'd recommend starting small and focusing on expanding shipping to a smaller number of countries before shipping worldwide immediately. Whilst this depends on your products and your audience, you may wish to focus first on selling into Canada (and/ or Mexico), given the geographical proximity to these countries to the United States. Starting out with a smaller number of closer nations will allow you to focus in on the nuances of selling into these countries, and better plan out your international shipping strategy before you look to expand into other regions of the world.
It's important to remember that each store's shipping strategy is different, and there will be instances where businesses are even offering shipping rates at a loss in order to entice customers in from abroad. There's no right or wrong approach here, but you will want to consider the value of international shipping, both in terms of your resources and your time. I'd encourage you to research the process of selling into these countries - namely the cost for you to ship what would be considered a standard order of your goods, and what duties/ taxes the customer may be liable to pay - and you'll then be in a better position to decide how you to wish to proceed. After identifying the countries you'd like to expand into, you may discover that, for example, you can sell to Canada and EU nations without losing money, whilst it may not be cost-effective to ship to Australia and New Zealand.
My recommendation would be to check out our guide on this topic: International Shipping: Everything You Need to Know to Deliver Beyond Your Borders. This is a superb resource that covers the main factors you'll want to consider when shipping abroad, and will provide you with the recommended steps we believe merchants should take when expanding their customer base into other countries.
I hope this helps but please let me know if you have any further questions on this!
Victor | Shopify Social Care