What to wear to spain?

I’m going to Spain in the middle of april with my school. I know the temps will be in the 70s but cooler at night, but what sorts of things should I bring? Shorts? (all I have is short shorts) Jeans? Dresses? I will be bringing a few scarves too. What about going in cathedrals and such?

What about shoes? I’m not really interested in wearing a clunky pair of tennis shoes the whole time, as it will ruin my outfit.. haha but are there any other options? Should I buy vans or something? Any suggestions would help!

Thanks a bunch! Also, I’m going in a group of 30 so I’m not totally interested in blending in with the locals as we will look like a crazy group of tourists anyway. 🙂