The honest answer is it just takes more practice.
As far as the technique itself goes, try and take note of how your hand and arm feel when the bachi is hitting each string. If you’re mindful of it, you will start to internalize how that physical placement feels and develop muscle memory. Looking at your hand to help with your aim can be helpful, but don’t overdo it. Turning your head down and to the side like that is going to pull your shoulders out of a good, level position and will probably create problems elsewhere.
Proper form is important to keep in mind, as you can develop incorrect muscle memory if you’re not careful. Watch through this Bachido course a few times and mimic along with your instrument: https://bachido.com/school/body-mechanics
A lot of the time, playing way slower than you think you need to can help a lot. Hypothetically, if you’re practicing with a metronome, which I’d strongly recommend, and you’re currently around 100bpm, try dropping it to 60bpm and go from there. If you keep messing up, keep dropping it by 5bpm or so until you can play without mistakes. Then you just work your way back up.
Playing slowly can feel discouraging, especially if you’re used to playing faster, but it can prevent you from developing bad habits or sloppy playing. You’ll also find that you need much less work on some techniques vs others, depending on how naturally they come to you.
Biggest thing is to keep practicing even when the slowness kills some of your motivation, because it can definitely feel draining when you’ve been practicing slow strikes on open strings for hours over the course of a week or more. The reward from improving your technique and comfort with the instrument is worth it though, and it makes future slow practice a lot easier when you keep that in mind.
Hope that helps.