A few things I forgot to mention:
1) Write your exercises in a notebook by hand, not into your computer. I won't go into all the various reasons why you need to do it this way, just do. If you don't have a notebook for the first day, hand write on something and transfer it into a notebook later (or staple or paperclip). A brand NEW notebook is best, one that you dedicate to this project alone. I use a giant hardback artist sketchbook because I like the freedom of unlined pages. For each of my scripts I have a notebook for exercises and a binder for anything else (such as research, typed and printed notes, outlines, etc).
2) Write in one colour and when you are done with all your exercises for the day, read what you've written. Take a different coloured pen and mark things that you like and/or make notes in the margins. Anything. Could be a name you just made up that you want to keep. Could be an idea on how to end the story. Could be an image you want to include. Could be something you want to explore further. I use black for the exercises and red for the notes and underlining simply because it stands out. When I think I've written something that will later become a scene in the script, I circle the whole paragraph in red and star it.
3) If you ever freeze up (usually cuz you switched from your gut back to your mind), simply repeat the opening start line. So if you started the exercise with "This is a story about..." write that and it will kickstart you again. If it doesn't, write anything! Keep a handy phrase that you jump into. I like to write "I'm so grateful that..." Just because I like feeling grateful.
4) Get yourself a timer for your writings. Don't depend upon a clock or watch (unless your watch has a nifty timer-alarm on it). You can get one from any kitchen store. I use the Pillsbury Doughboy Magnetic Digital Timer (Item #962), which has lasted me for years. When I say write for 5 minutes without stopping, I mean write for 5 minutes without stopping. But Danika, my hand hurts! Tough love, baby. Tough love.
5) Someone asked me what happens if you miss a day. My answer: you don't.