Careless or irresponsible smoking is the number one cause of home fire deaths.
Do not extinguish smoked articles in pots for plants/flowers. The soil may contain peat moss, shredded wood and bark that can easily ignite.
Use larger ashtrays that can't be knocked over and deeper ashtrays to prevent cinders from spilling easily.
Ideally, empty ashes into a metal container, otherwise before placing in garbage ensure that several hours have passed since the last item smoked has been extinguished. Spray butts with water to be safe.
Smokers should smoke away from upholstered material in general. Cinders or ember can smolder in upholstery cushions for hours before igniting.
In general it is rather wise for smokers to go smoke outside in the fresh air for numerous reasons.
Alcohol and fire are always a dangerous mix. Stay vigilant and make sure all cinders are properly extinguished, during parties, social events or gatherings.