Hi GREfocus.
The key to mastering the GRE is just to work topic by topic, mastering one topic at a time until you've mastered enough topics to achieve your score goal.
To master a topic, you first learn the relevant concepts and strategies and then answer practice questions involving that topic until you get them correct consistently.
When you're practicing, what works best is to start off doing questions untimed, giving yourself time to get the questions correct and learn. Then, once you're achieving high accuracy in a question type and understand how to answer questions of that type, you work on reducing your time per question until you're answering them at test pace.
For more on how to prepare for the GRE, see this post.
The Best Way to Study for the GRE: 7 Strategies for Success