i found that until i saw what the equations meant in 'real' terms, i couldn't get any sort of a grasp on tensor calculus. working through the problems in D'Inverno's 'Introducing Einstein's Relativity' helped me understand.
there was a small pdf i found somewhere on the web about common mistakes that people make when working with tensors. must try and see if i can find it.
found it. section 3 and 4. i fell foul of some of the common pitfalls working with tensors myself.