Get the blue book and barron's. Take a practice test from the blue book every saturday morning. Try to create the conditions (breaks, timer, stress). You want to get your body and brain used to Saturday morning tests.
When you take your first practice, identify every "knowledge gap" you have when you review. That is, if you get a triangle question wrong, you know that you need to review triangles.
Go into Barrons (or online, or whatever) and learn the concept. After you review all those concepts, do the practice problems in barrons, and feel comfortable with the concepts, take your time to understand backsolving and plugging in techniques.
Then rinse, wash, and repeat.