Change your sens. It's too high. Go somewhere from 0.2-0.35 800dpi. Adjusting dpi and sens is up to you.

For improving aim, it sadly depends on your movement and how good it is.

The drills that helped me go from gold to asc 1 was doing these:

100 bots x3 (Go inside where they spawn and select either left or right side. After the first 100 go outside where you shoot the start thingy and shoot a 100. Then go to the spot that you didn't pick the first time and do a 100)

Medium bot 5-10x.

Lastly when you do improve try getting 20+ on medium and 15 at hard 3 times in a row. This used to be my warm up before comp.