Carefully select the trigger images according to the provided rules
Take the time and prepare each trigger in the best way (cropping/etc.)
Always test every image right after upload – just add a simple text element or image and check the tracking performance on your test devices
Test on different phones (Android and iOS) and in different lighting conditions (daylight vs. electrical light / diffuse vs. direct light / etc.)!
Quick-tests by scanning the trigger on your screen are fine but not sufficient to get a real test result, so always test the trigger printed (as close to the final print product as possible)