How many did you notice? A few I saw were:

(SPOILER)Garnet's real name, Sarah and her Mother's name, Jane, are also the names of the Princess and Queen in FF1.

In the weapon store in Lindblum, there are a few swords on the wall. One of them is the arabic version of a Grand Sword. If you check that with Zidane, he says: "I remember a guy with spikey, blonde hair that used to carry something like that"

And, perhaps the obvious one, Vivi is of course dressed like the traditional black mage all the way through, and when you first meet Garnet on the stairs, she is dressed in the traditional white mage outfit.