Safety Surveys
Most fire departments do fire safety surveys upon request by the occupant. Keep in mind that this survey is voluntary, which means you have to mind your P's and Q's even moreso than normal. Be professional, polite, and respect their privacy.
Overall- Of course, spend the majority of your focus on the common causes of a residential fire. Keep an eye out for cooking equipment, heating equipment, exposed or faulty wiring, open flames (candles and fireplaces), and smoking materials. Don't forget that the fire hazards in a house with competent adults are different than those of a house with mentally disabled children or senior citizens. Recommend having a fire extinguisher somewhere in the house if there isn't one. After all, the cost of a fire extinguisher is a lot less than the cost of a new kitchen.
Outside- Make sure the house number is easy to see. The guy driving the engine or ambulance will appreciate it. Any sort of piled combustibles like a trash pile present a fire hazard, as well as any plants that need to be trimmed down. It's also a good idea to keep vegetation away from vehicles to prevent a carfire from turning into a structure fire. And hey, if you have the time, recommend the annual chimney sweeping.
Inside- It's important to explain to a homeowner exactly why things like overloading a circuit is a fire hazard, instead of just pointing at it and calling them an idiot. Point out alternate exit routes, and suggest practicing a fire drill if they have a family.
Smoke Alarms are a common device used in structures to alert the occupants of the presence of smoke and/or fire, and a huge part of saving lives. Yes, I hate them too (because I burn something in the oven every week), but they serve a great purpose. It's been shown that the risk of death is cut by 50% in a house with working smoke alarms. They should be installed in every sleeping room of the home. If they aren't mounted on the ceiling, they should be within a foot of the ceiling. For obvious reasons, they shouldn't be near a window, door, or vent. Replace the batteries every year, and use the test button once a month.
Bedrooms are a common origin for a fire. Smoking in bed causes only about 5% of fires, but account for almost 25% of civilian fire deaths. People die from this all the time. Stress this issue to the homeowner. Another room of similar importance is the kitchen.
Nearly 25% of residential fires take place in the kitchen, usually the result of a cooking accident (I've caused a few myself). Keep an eye out for flammable material that spends too much time near a hot appliance. Again, make sure the homeowner understands the that leaving anything cooking unattended or overloading a circuit is bad news bears. As I said before, get a fire extinguisher placed nearby. Living room fires are typically caused by bad electrical equipment or again, careless smoking.
Storage areas like the garage or tool shed are just waiting to go up in flames. Let's try to avoid storing old gasoline right next to an outlet, ok? When you're done going over each room and have gathered an overall picture of the residence, summarize it to the homeowner. Give them a big picture, as well as the specific points.
Before you leave, it's not a bad idea to remember the floorplan of the house if this is your first due. It could be helpful in a fire later on.