How do i gain control and talk slower?

How do i gain control and talk slower? Most people stutter a lot less when they speak slowly, me included. But i have for some reason a really hard time to slow down my speech. My regular talk speed is pretty fast. And i am usually unable to slow down my speech no matter how much i think about it. It is only under certain circumstances where i am able be calm and gain control over the speed of my speech. Does anyone else have these issues? or do you have any advice on slowing down my speech?