how do you avoid waves all over the place

i brush my to ways......startin from the back i go up n around in a ccircular motion til i hit my top then go on the other side of my back n do the same......n i also brush the top foward, middle of back st8 down.....corners of back slanted.....n sides foward wit a slight......SLIGHT slant.....lik wen im brushin in tha shower it feels lik im goin st8 foward but wen i brush in tha mirror its not tottally st8 but close enuff(twista motivated me to change my pattern uz i used to brush diagonnally)

im afraid to get waves that not in a particular pattern how do u avoid that