How do you make caramel correctly

A couple tips-
First of all, when you are cooking the very beginnign stages of it, before the sugar is dissolved, keep the lid on. This will help it from crystalizing (it's much more effective than brushing the edges with water I find).
Second, Have everything measured before you start! It can start to change quickly and if will give you peace of mind to know it's all ready.
I've got a full tutorial on my blog with pictures every step of the way- check it out! http://liviasweets.com/post/37216197174/tuesday-tutorials-gingerbread-caramels

Oh, I should add that I make caramel over medium to medium high heat, although I can't profess that this is the best way. Just how I like to do it.

For caramel, you don't really need a candy thermometer. All you need to do is melt sugar with a little water (I use 1/4 cup water to 1 cup sugar) and cook without stirring it until it is deep amber (stirring can cause the caramel to crystallize when it hits the relatively cool sides of the pan). Remove it from the heat, whisk in cream (1/2 cup for 1 cup sugar) and butter (1 stick cut into small cubes), and add vanilla and salt if you like. Then you're good to go. This is assuming you're making a caramel sauce rather than soft or hard caramel candies.

yes that's how I know as the temp increased the caramel broke, as it was getting close to 300 it broke :(

Did you use a candy thermometer?