Well after failing with a 638 / 1000 last week, I took the test again after studying strictly practice tests and I passed this morning with a 868/1000. I studied for 4 months off an on.The game changer folks, is work through practice exams any and all help, this is the only way in my opinion your going to feel comfertable with the tests questions and have a good idea of the wording of questions. Read the study books, do your test labs on R2 with, then for the last two weeks, do practice tests and test your skills and you'll be fine. Dont rely on Sybex practice tests those are too easy. Try the Kaplan self test software
Kaplan SelfTest Microsoft MCTS 70-640 Training Products - Practice tests and Online Courses - 70-640. Good luck