How do I change the candy per second rate in the JavaScript console?

Hit F12 if you are using Chrome or IE, or Ctrl + Shift + K on Firefox, or Ctrl + Shift + I on Opera, then click on Console. Type in the command and then hit enter.

candies.candiesPerSecond = 100;

(You can change 100 to what ever number you want).

If you are confused about any of this refer to the following screenshot.