what can i wear with a denim dress?

[sydy]

so i just bought this really cute strapless denim dress. i love it, but i can't wear it to school unless i cover up a little bit. the dress is like a light blue-gray and i was planning to wear black tights with it.

im not sure what to wear on top: a cardigan or a jacket over, or a shirt under? and what kind of jacket or shirt?
thanks for your help!