Starting at the ceiling I measured down 10 1/4″ all along the wall, then using my long level I drew a line connecting the marks at the same time making sure my marks are level. I continued down the wall measuring 10 1/4″ down from the line above marking and adding a new line. Once complete I tape outside of the stripe to be painted. I also made sure to put the tape just outside my pencil line so that they would be painted over, leaving less clean up.
One extra step I like to take is to add a few small strips of tape inside each stripe I will not be painting. I have been known to paint the wrong stripe so this is a safety measure before the paint comes out.