What's up, dirty? First of all, are you finishing the entire VR section? If you are rushing through it, you are probably missing a lot of questions as a result. You need to practice as much as you can using all the practice tests that you can get your hands on and learn to budget your time during the test. Use a timer right in front of you to pace yourself.
Also, you should redo old practice tests after several weeks when you have forgotten the answers. Keep records of your performance. If you are consistently making the same errors, learn why and hopefully you can stop making them.
Finally, take Kaplan or something. Don't waste your time with anything besides TPR or Kaplan materials. I haven't used examkrackers so I won't make any claims, but stuff like Barron's, Peterson's, etc. are total crap. I'm not exactly sure if the review courses' "high yield" techniques for VR are the magic bullet they claim they are, but the practice you will get in a prep course is essential and plays a big part in your performance on test day. Also, the VR questions are fairly formulaic, and the review courses will give you an idea of what to expect.
It is possible to improve. Keep working and good luck.