This is SO simple that it really doesn't even need a step-by-step tutorial (not that that's ever stopped me from doing one anyway!). The results are lovely, the combinations endless, and you can swap out the colors/patterns as often as you want or use my handy trick for making it a permanent part of the candle.
You can apply your tape strip-by-strip to the candle, or you can do like I did - lay out a sheet of waxed paper and apply your strips to the waxed paper, slightly overlapping each strip with the last. This gives you a little more flexibility to play with pattern and color arrangement before sticking them on to your candle.
Peel up the strips as one large piece.
Start wrapping the washi tape around your candle, peeling it off of the waxed paper as you wrap.
Smooth it all out, and you're finished - easy peasy! If you'd like to make the tape a permanent part of the candle, set your blow dryer to the highest heat setting and quickly give the candle a few blasts of hot air, using your finger to smooth and lightly press the tape into the top layer of slightly melted wax to permanently adhere it to the candle.
Trust me when I say that you're going to wish you have a dozen or so candles to washi, so stock up and/or raid your cabinets and shelves! I'm heading back to the store to pick up some more in different shapes and sizes because it's definitely addictive (and a great way to make use of the giant washi tape collection I have!).