I did this subject last year, I'd say make sure you understand the theory and are able to apply it. And then just practice, practice and practice some more.
I'm doing it the 2nd time this year.
Try to draw as many different diagrams/sentences as possible - vice versa.
Practice does help a lot, but make certain that you understand the differences between all the type of diagrams - it'll make a big difference exam time. I got totally confused....
Reanie
Don't be fooled by your assignment marks, doing the diagrams in an exam with a time limit is not that easy. Be sure you know all the diagrams well, and you can only do that by practicing a lot.