We recommend prioritizing markets based on:

1. Existing traffic and conversions from international users
2. Market size and search volume for your keywords
3. Competition intensity in each potential market
4. Operational ease of serving the market (shipping logistics, regulations, etc.)
5. Language overlap with existing content (e.g., expanding from US to UK is easier than US to Japan)

Often, the best first international markets aren't the largest ones, but those where you can most easily succeed with your current resources.