How can you tell if a timing belt was put on right?

To determine if a timing belt was installed correctly, check for proper alignment of the timing marks on the crankshaft and camshaft pulleys, ensuring they match the manufacturer's specifications. Look for any excessive slack or tension in the belt; it should have the correct amount of tension without being too tight or too loose. Additionally, listen for any unusual noises when the engine is running, as knocking or grinding sounds can indicate misalignment or improper installation. Finally, ensure that all pulleys and accessories are functioning smoothly without any binding.