I was told to make a wish when the clasp of your necklace touches the pendant. Also when you throw a penny in a wishing well or fountain. Or blowing out candles on a birthday cake.
Forklore says to use a fallen eyelash to make a wish upon. Then there's a shooting star. What other items have you heard about making wishing upon?
We always made wishes when a dandelion went to seed and blew apart.

On the first star you see at night
Ladybugs!