Take an old glass jar and give it a good old wash and remove any labels by soaking the jar in warm water.
Unroll your sticky back chalkboard paper (I got mine from a local stationers)
Cut out a square, use the grid on the back to keep it straight.
Using a white chalk pen, your your design freehand onto your chalkboard square.
Peel back the sticky backing and stick the square to your jar. If you change your mind about the design, you can simply peel off the sticker and put a new one on - they are easy to remove.