Start by listing the information you would struggle to replace: photographs, documents, creative projects, and device settings. Decide how often those files change and how frequently you should make a new copy. A routine is more valuable than a complicated system that is difficult to remember, so choose a schedule and method you can maintain.
Keep copies in more than one place. Automatic cloud syncing can help protect files from a lost device, while an external drive can provide a separate local copy. These methods solve different problems, and a synchronized folder may also reproduce accidental deletions. Check what is included, how long deleted items remain recoverable, and whether sensitive data is protected appropriately.
Test recovery rather than assuming a backup works. Open a few files from the saved copy and learn how to restore an individual item before an emergency occurs. Keep an external drive disconnected when it is not being used for backup, and store a second copy away from the main device when practical. Review the routine after adding new devices or changing where you keep important files.