First things first, make sure you are trying to curl your hair with the right kind of flat iron. Here are some things to look for -
1 - Look for a skinny flat iron, one that is around 1 inch in diameter.
2 - Look for a flat iron with rounded edges.
When you look down the barrel of the flat iron (similar to how you would look down the barrel of a gun), the closed flat iron should form a circle, not a rectangle or square. A flat iron that is too square will create kinks.
3 - Look for a flat iron that gets somewhat hot on the outside of the plates as well.
You can curl with pretty much any flat iron, but a flat iron that meets these requirements will make your job a lot easier.
Learn how to create flat iron curls in the video below!