This is another one for context clues!
Llevar can be used for several things: wear (clothing), bring, carry.
Traer is a synonym, but it depends on what your saying. Some phrases employ the words in different ways.
You need a dictionary that will give you example phrases or context information:
http://dictionary.cambridge.org/defi...&dict=S&lang=S Llevar
http://dictionary.cambridge.org/defi...&dict=S&lang=S Traer