#20 can be elaborated by doing it once saying "What date is is? Which year!", then "Darn! It didn't work", and walk out. Put the clothes aside, and one year later on the exact same date, wear the same clothes and do it in the same store. This time you go "It worked! It worked!".

Works best in a store where you can be reasonable sure the same guy will be the next year. Do it in several stores to enhance chances of success. Also, wearing some easy to remember clothes/headgear etc. will increase the chance of someone remembers you.