I have taken the GRE test previously and have been involved in consulting on GRE topics and preparation for the last 2 years. Here’s a presentation I prepared where I’ve discussed a lot of topics ranging from when to take the test, which one to prepare from, the mock tests to take:
Most of the methods I’ve discussed are for free. There is also a Secret Group on Facebook which has helped me and many other people around the world in their GRE prep work. Please let me know if you want me to add you to the group.