The safety of others and yourself is the primary concern when launching your UFO.   Make sure your flight path is clear.  Check overhead for trees and powerlines.

Check your weather conditions.   It's no good if it's raining or seriously windy.   Choose a cool clear night with little or no wind for the best results.  If you can find an elevated launch site, this is even better.

Locate a clear area on the ground with no flammable objects.  When igniting the power source, keep the flame away from your face and the edges of the UFO.  And never let the UFO go until you feel it push upwards.

Always use your common sense and consider others.