I am adding a few swatches of dark blond to my precolored hair for low lights, any tips?

Last time I tried to color my pre lightened blond hair to a reddish shade, it came our like a checkerboard, some brown, some red, some orange, some grey-it was horrible. It cost almost $200.00 to fix. At the time, I didn't try very hard, just quickly put it all over and it was a nightmare. This time, I did a pre-swatch test and the color is not patchy, it is all one color of dark blond. I plan on using foil to keep the 2 colors apart.

I am adding a few swatches of dark blond to my precolored hair for low lights, any tips?

you shouldnt colour your hair all the time, bcuz you have to keep with it for the rest of your life (covering roots, and re dying bcuz of fading colour) and this will really damage your hair ALOT! plz dont colour your hair bcuz later, it will become extremly brittle, and damaged!