For example should I get them my normal shoe size i.e 6 or should I get them a size down?

Try them on at the store, if at all possible. Many brands of dance shoes tend to run really small. For instance, when I took a tap class in college, I bought tap shoes in an 8 when I really normally wear a 7 1/2, and they were STILL way too small! I should have gone for probably an 8 1/2. My toes were crying the whole semester, and I developed an ingrown toenail that still gives me occasional trouble 7 years later. Get a 7 if you wear a 6.