Check the current requirements of your chosen payment provider, link an eligible card where possible, and test it with a small purchase after arrival.
Do the setup before the queue
Download required apps, verify accounts, and save key screens before you are trying to pay for a train or dinner. Connectivity can make the process slower than expected.
Keep a practical fallback
Foreign cards and cash may work differently by location. Carry a modest backup and ask your hotel for current, local suggestions if an app fails.