Read the questions
I just took Network+ and scraped in on 860. The exam is definitely more difficult than any of the test exams I have seen - but having said that I got 95+% which is about the same as the tests. Some of the questions wording takes 2 or 3 reads to get in your head what they are actually asking. Books are OK but I think just like A+ experience is what gets you through. Quite a few questions on Netware scenarios which I wasn't really expecting. All the protocols and OSI questions are a doddle if you know the subject but make sure you read the questions properly for the troubleshooting questions, you need to get it straight in your head before committing to an answer.