Hello! I am currently a sophomore in high school who recently took the PSAT for the first time and scored a 1230. I need to get a 1420+ to be where I need to be in order to get into the colleges I am interested in. I did not practice at all for the PSAT this year and I need some advice on how to score better for next year. I got a 680 on R+WR (although my writing score wasn’t great – missed 9) and a 550 on M (atrocious for where I need to be). I honestly could care less about reading because I scored in the 98th percentile, but I need advice on my math and writing scores. Thank you! 
I really wouldn’t worry too much! I scored a 1260 on my sophomore PSAT and was able to get that up to a 1510 on the recent December SAT (I’m a Junior). I started prepping the summer before Junior year and I found that to be plenty of time for me just by using Khan Academy! I wouldn’t stress yourself out with it too much during sophomore year - your way ahead of the game.
Did you use any specific prep books?
Bump
I am a fan of Khan Academy. It is free and it is individually tailored to you based on your PSAT.
Starting around August of junior year, my son began doing a few Khan Academy activities (practice tests and work, I believe) on some weekends. In October and/or November, he also looked at some math pages in the “advanced” Steve Warner book. He did not go too crazy, but he definitely built his familiarity with the test. He took it in December of his junior year— one and done.
We had bought him other prep books for the SAT and ACT, but he never used them.