Campfires are a lovely part of the outdoors and are responsible for a considerable part of the nostalgia of trips with family and friends. However, being cognizant of fires, especially in areas where hazards exist, is key to making sure you and the nature around you can be safe.
RULE #1: Make sure campfires are allowed in your areas.
In arid/desert/dry climates, there may be a seasonality to fires or limitations to areas of a park where they are allowed. Read up on the park before you enter, park rangers have little tolerance for putting safety second.
RULE #2 Determine where they're allowed.
Campgrounds: Stick to designated areas in developed sites. If the area is undeveloped, ensure that the site is safe by identifying that there are no low hanging trees/branches, or brush nearby.
Backcountry: Try to use an existing fire ring if possible. If there are none, try to find a shielded non-windy site, that is away from trees and brush. Ideally, the pit of your fire should have a sand, gravel or soil bottom. Think twice before using a soil bottom before you use, as excessive heat exposure during a fire may prevent growth in this area in the future.
RULE #3 Properly & Fully Extinguish the Fire
Ideally, pouring water on a fire in a slow and controlled fashion is the ideal method. Stirring the ashes and then applying more water as needed. This process may need to be repeated several times. You must be certain that a fire and its embers are out before you depart from your campsite. Sand, if available, is an alternative method to be used in extreme circumstances although heat may continue to be present beneath this causing insulation of coals and ultimately fire if uncovered at a later point.