Put their name in lights.
If you live together, embroider your initials and theirs on your table napkins.
Fill a scrapbook with photographs of them, and add quotes of the wittiest, nicest, funniest things they’ve said.
Make a playlist of their favourite songs.
Give them vouchers for back rubs – you’re the masseuse.
Arrange a surprise reunion lunch with their favourite, oldest best friends.
Put their name in lights.
Wash their car. (Or just their hair, salon style.)
Give them a mani or pedicure.
Prepare a week’s worth of special Valentine-themed, packed lunches to take to work – with a different surprise in each lunch box.