Did the poster bring a smile to your face? How many of you were Girl Scouts? I joined a Brownie troop in second grade and moved on to the Girl Scouts staying with it through the eighth grade. Thus, this poster amused and it spoke to me, too. I learned in those early years that the Girl Scout Promise was for real, not just words that were memorized and spit out when asked. It meant something. In the same way, you can make this motto an important part of your writing life.
Look at what this girl is telling us. First she says You are a writer. That alone should give you a sense of accomplishment. Do you consider yourself a writer every day? If you've written even one story, one poem, or one essay, you are most assuredly a writer. Believe it.
Next, she tells you Write. One simple word, one direction, one thing for you to do today. She doesn't say to write two chapters in a book or 1000 words. She never tells you to finish a full story. All you need to do is write any amount.
She follows up with why you should write today. That is your task, your duty, and your honor for today. If you believe that you are a writer, then it is most certainly something you must do today.
She ends with two words. Simply write. The only way to continue to be a writer is to follow this advice.
Consider printing the poster and putting it somewhere near your desk where you write. Look at it every day. Believe what it says. It will serve you well.