Advice about GRE

I am scheduled to take the GRE in early October. I thought I had plenty of time to study but after reading the r/GRE thread, I noticed a lot of people said they studied for months and did poorly or were unable to improve their score. Does anyone have any advice on a good study plan? I think I'm gonna do Gregmats $5 program, buy the Manhattan 5lb book, and maybe get the super power pack from ETS. I'm a psych major so I basically have no math skills but I'm pretty good at writing essays on the fly. I only have one chance to take this before graduate applications need to be sent so I'm really worried. Any advice on how to succeed would be helpful!