DownOnWax hits the right points for physical characteristic and high..
Being bagseed, hopefully you still have the bag.. The smell of the weed from the bag is a good tip, too -- well-cured (and sometimes seedy) sativas have a spicy smell --- smells like something you might crush up put on your food, or a piney smell. Inidicas have that greasy, hashy odor with a little piney smell mixed in. I've got a bag of Thai and one of superskunk in front of me right now -- totally distinctive on smell, high, and phsyical appearance.
Another thing you might recall from the bag --- stem thickness and structure in the tops. Inidica = stout, short-noded stem all the way up Sativa = thin, spindly, zig-zag stems at the top.