This is what the different signs would best appreciate.
Aries: Write them a heart-felt thank you note or card.
Taurus: Give them a gift certificate to their favorite coffee shop or shopping store.
Gemini: Bake them something.
Leo: Ask them about their day.
Cancer: Walk them to the bus stop or home from school.
Virgo: Lend them a hand on something they are working on.
I use it as an easy conversation starter and as a casual excuse for my behavior ;D