Generators are great. . . especially when you lose power. However, generators can be dangerous when not used properly.
Only operate your generator outside in a dry area. Never take a generator inside the home or garage.
If you are using extension cords make sure you use the proper sized cords.
Avoid overloading your generator by plugging in too many appliances.
If you want to wire your generator directly into your home's existing electrical system you should have a licensed electrician hook up your generator. . . in most cases you will need to throw a switch before using your generator.
Only fuel your generator when it is not running and keep all fuel away from the generator and outside the home.
Finally, if you see an electical repair crew working in the area it's a good idea to let them know you're using a generator. This will keep them safe and they can advise you when you'll be able to switch off the generator as power is restored to the area.