Taking the Next Steps in my High School Career

Last year I was a freshmen, righty, pitching 72 mph probably hitting 74-75 a couple times. The division my school plays in is one of the most competitive divisions in the country, North Jersey Baseball is a big deal down here. I was what you call a work horse for my freshmen team. I was the third pitcher in the rotation behind a righty who threw 84 mph and a lefty who threw 81 mph. The difference between me and them was my efficiency as I possesed a 12/6 curve tht froze many batters and was very accurate. I threw around 50 innings that freshmen season with a 5 and 1 record. I take pride in myself as a pitcher being able to hit spots and not walk batters. I feel however that adding more velocity would bring me to a whole new level.

About myself
Just turned 16
I’m 6’0" 160
Throw 72-73 consistently
Legit 12/6 curve
Changeup is a work in progress (is a changeup really effective even if you’re not throwing 80+?)

What should I look to improve on and how should I do so before my sophomore season? I get the sense that I’m going to be a borderline varsity pitcher next year and an increased velocity could secure that spot for me.