There's a relation between how to use a flat iron and what is a flat iron and how to be careful with a flat iron.
Two things you should pay special attention before you even think to use a flat iron are: the temperature and the plates.
The temperature is extremely important, some straighteners do not give you the option to change the temperature, run from these ones, with this type of straighteners you have no control over the temperature and also you have no idea of the temperature that you are using, you may be using excess heat on your hair without having notion, which only damage your hair.
A good straightener will give you several options of temperature, generally between 140 and 210, if you have thicker hair, with plenty of texture and difficult to control make sure you flatter reaches higher temperatures, up to 210º is a good temperature. If you have thin hair do not need a lot of heat.
Another thing that is nice to have a straightener is a quick warming, do not want to get 5-10 minutes waiting that your straightener becomes hot, between 20 and 60 seconds is a long time. Make sure that the straightener warns as it reaches the desired temperature, some whistle, others light a little light, mine for exemple, stops flashing the screen when it's ready.
The plates are the most important factor in a flatter, are the cards that are in contact with your hair and want to straight well and quickly without the need to spend more than twice so that the strand is completely stretched.
It is also important that the plates are good because the best are the plates will less damage your hair.
More importante stuff? Especially the size and material. As for size, the longer your wider hair should be the plate, there are thin plates made especially for short hair, the width varies between 2 cm and 8 cm, I think a 3cm to 4cm is the most versatile board an intermediate plate is easy to use because it gives you control over a plate and these have the option of turning the ends into or out curling and even!
If you want your straightener also curling, a modeler basically demand for flat and rounded sides in the straightener and a not very large plate.
As the material never use a metal plate, EVER! It's like a frying pan for hair and you do not want to fry your hair ?! I thought so ... a good board is usually either ceramic or covered with a stone like tourmaline and jade. This kind of materials do not damage both the hair and is much healthier for the hair, and leave shiny and frizz-free hair for much longer, this is due to the negative ions present in these materials that negate the positive ions that are on hair and mainly cause frizz.
It also leaves more shiny hair by closing the hair cuticle, which causes the hair strands reflect more light. A ceramic plate or one of these stones evenly distribute heat through his hair.
It's the little things that make some straighteners better than others, the position of the button on and off must be positioned so that it does not hang the straightener by accident. The cable should be fully rotating, do not want to get entangled in the cord.
The material of which the outside is made should be a material that will not peel over time. Another detail, especially for the forgotten, is a flatter you to turn off automatically after 1 hour.
So, how to use a Flat iron? With care and love and following this rules!