Simple Question: How to Get Better?

First, if it hasn't already been mentioned to you by your coach or someone, always practice with some specific intent(s). A lot of young men your age will do bullpens or flat ground work without much, if any, intent. . . which tends to be very unproductive. But from what you've mentioned, it sounds like you do have intent in your workouts or you wouldn't be asking such questions. GOOD for you. I thought I'd mention it just to emphasize it.

IMHO, doing some flat ground work is a GOOD thing and SHOULD be done between any bullpen/mound work. Just how much is hard to say as you didn't really say how many pitches your bullpens consist of. I'd say if your bullpens consist of 30-35 pitches, then **** 15 or 20 for a little flat ground work would be a good idea (particularly this time of year as you prepare for the start of the season). And I might add, don't forget to do some long toss as part of your workout routine.

What you should focus on really depends on where your strengths and weaknesses are. Consistency, or "command", is probably the hardest part for HS pitchers where age and maturity is a large factor. And there's not a whole lot you can do about that except to be patient and work hard and as you mature that'll all pay off. So, with that said, I'd say if you have any problems in keeping the ball down, that should be a big part of what you should work on first. If you've got 2,3 or 4 pitches, work on keeping them all down (even below the knees). You'll want to do some work on developing consistency for pitching on the inside now that BBCOR bats are being used. And again, you'll want to develop your command of your various pitches to place them in such locations.

And lastly (you've probably already been told this), players play in their game very much like they practice. So, when you're doing bullpens or even flat-ground work, do it like you would in a game. That is, try to have the same kind of tempo and purpose in a large part of your workout, mixing your pitches up so your mind, body and arm is used the feeling of doing so.

Hopefully, you've got a good pitching coach that you can communicate well with. He should be able to see what you're doing and what you probably should be working on most at any particular point. We here cannot see what your daily workouts are like, so suggestions like I've made here are really only good generally to a certain extent. But I hope it helps give you some ideas.

Good luck and have a GREAT season.

First, good luck on the upcoming season!

To add to what Truman said (good advise), use your bullpens and flat ground to not only work on your location, which is key for any good pitcher, but also use them to work on your arm slot and arm speed on all of your pitches. Try to get your arm speed and slot the same on all pitches.

"First, if it hasn't already been mentioned to you by your coach or someone, always practice with some specific intent(s)."

Seems obvious, right? As usual, things that are obvious generally aren't followed

Kids screwing around in the weight room or aimlessly throwing for no reason produces nothing of value. Well said.