The very first burn of a pillar candle is the most important. Allow candle to burn 1 hour for every one in in diameter of the candle. This will create the "melt pool" that will help you candle to completely consume itself. The liquid wax should reach the edge of the candle but not spill over.
Handle with care; glass containers are fragile. Do not use if the container is cracked, chipped or scratched. Do not refill with wax.
Following the safety rules above should minimize the chances of needing the following instructions. Note that wax removal is often as damaging to the surface as the wax was, so make every effort to avoid spills or drips.