Wash and dry jars and give them a rinse with rubbing alcohol. Be careful not to touch the outsides of the jars with your fingers as the paint can repel from the oils in your hands.
When jars are dry, use a three dimensional writing paint to draw designs on the sides of the jars. Allow to dry as least 5 hours, preferably overnight.
Spray the outside of the jar with spray paint; applying several thin coats at 30 minute intervals. Several thin coats is preferable to a couple of thick coats as thicker coats tend to run. Let dry overnight.