Firstly, make sure you position your electric heater correctly. Electric heaters should be placed on even, or level, hard and nonflammable surfaces, such as a tile floor. Carpeted or wooden floors are therefore unsafe to put your electric heater on.
Another important aspect of positioning your electric heater safely is to note what is around it. Flammable materials, such as fabric curtains, bedding, carpets or furniture should be kept at a reasonable distance away from your heater. A good way to tell if flammable materials are too close to your heat source is to feel the material. If it is hot, move your heater to avoid a fire risk.
Never leave your heater on without supervision. This means that when going to sleep at night, or when leaving your property, all electric heaters should be switched off.
Ask the right questions when you purchase your heater. Ensure that the heater has been tested and certified according to acceptable safety standards and never buy untested or suspiciously cheap products. Rather spend a bit more and have the peace of mind knowing you have invested in a product that poses no threat.
Finally, if you are going to make use of electric heaters, one of the best precautions to take is a smoke alarm on each level of the house, if your home is more than one level, and in each room.