I know this will sound cliche but 76 to 80 percent is pretty good on these practice exams. These practice exams are normally challenging so that it makes you go and read the answers to research more in depth.
The key is to understand the concepts and be able to understand them context. The N10-006 exam is more scenario driven and requires not only memorization but application too. The N10-005 exam is broad in the technologies covered. Remember that the Network+ exam coverage is to validate the knowledge and experience of a technician who has been working in the field up to 12 months. This lets the candidate know what is expected in knowledge. Someone in the field may be able to identify and understand the basic concepts and even configuration but not mastery of the domain objectives. I can only attest to you that if you've been watching the N10-005 shows, you've seen every single exam objective. You've been watching and listening to everything that will help you to understand the technology and will help you to understand the material to help you to be successful on the exam. I can also say that others have successfully passed the Network+ exam (N10-005) using our shows as part of their study methodology!
My best advice to use the practice exam to help you focus in on your weak areas from this point on. Do not use it anymore to try and get a higher score but to try and make sure you're understanding those domain objectives that you're still showing a weakness in.