Press the Strip of Tape to the Wall
Place the end dot on the tape you've already applied to the wall and press the strip to the wall.
Next, use a laser level to shoot a beam onto the second dot; pull the tape loose at that point. The beam from the level will show you exactly where to place the next strip of tape. (You can rent or buy a laser level. Just set it up in the middle of the room and you can turn it so it hits every wall as you work your way around the room.)
Tip: Remember that because you will be painting only every other stripe, you'll need to tape out the pattern so that every other stripe is outlined by the tape. Make sure to tape outside the chalk line; fresh paint will cover up the lines.
Tip: You can also make the lines with a chalk line. Use blue chalk because red or yellow is a permanent color.