I took the PSAT first as a sophomore and scored 180 with zero prep. I spent some weeks in the summer before my junior year to prep for PSAT using the SAT Blue Book. I was disappointed by my score as a junior - I got 198. There was no chance for an NMF.
So in February of my junior year, I started prepping for the June SAT. I scored 2260 on my first and only SAT attempt. So don’t let anyone say that the PSAT is a good indication of your SAT score. If I can make a jump of this magnitude, I am sure others can do it too.
Wow that’s great! 
@Musicschool2016 What prep books did you use?
I used Rocket Review, Grubers, Erica Meltzer’s Ultimate Grammar and the Blue Book. I used the Blue Book solely for test practice. The other books were for prepping for strategy and fundamentals. I would spend 30 minutes each day on the prep books and do 2 or 3 test sections from the Blue Book on Saturdays and Sundays. At first it seemed tedious but after 3 or 4 weeks, it became a routine and I never wavered from the routine.