Dear Doing the Best:
We are afraid that we don't have anything particularly insightful to offer other than common sense.
Practice, practice, practice! That is the mantra for success on the GRE. You should familiarize yourself with the content and format of the GRE. Take practice exams. Work hard and do your best. The amount of effort required to do well varies across individuals; it depends on your current knowledge and skills. We would expect a minimum of 2-month full-time effort, or many more months or part-time effort, depending on your current abilities.
Walk down to a bookstore or a library and get yourself a GRE guidebook, and start working. There are many self-help books available. We do not recommend any products or services, as a matter of policy and practice.
One final suggestion: if you can, study with a friend who is at least as ambitious as you are. Learning is more effective and more fun when it can be the result of a shared effort.