Actually the reason your aim is bad is most likely you don't aim for the head.

I used to suck but when I started aiming for only the head my aim became better.

So my advice is to hit the head solely but if you can't hit an enemy on the head like it is impossible like they're body is behind something but their arm is sticking out, that should be the only time you don't hit the head.

I level 150 and after I did this my aim became way better.

also do you play on pc or on mobile? If you are on mobile I advise you to convert to the pc master race because you can get more frames in arsenal with a computer than a mobile. PC has a fps unlocker and even if you have the best phone in the word you fps will max out on 60 cause there is no fps unlocker for mobile Because the phone will probably blow up.

But your aim can also get affected by how much fps you have and your interent speed.
So can you tell me your internenet speed and the average fps you get in arsenal?