I read an interview once with Matthew McConaughey, and he talked (among other things) about exercise and how some actors will have specialized exercise equipment flown to wherever they are so they can do the same routine they do anywhere they find themselves shooting. At the time, he was filming in Mexico, and he talked about running, and how the only thing he needed in order to run was a pair of shoes, and the only thing that he needed to do in order to start was lace them up.

He went on to talk about applying the same simple analogy to anything; how the only thing you need to do in order to be doing something was to start doing it, and that starting anything, while seeming to be a big obstacle was in fact as simple as lacing up your shoes.

Don't ever put emphasis on the beginning of something. Don't wait for the perfect moment, don't wait for inspiration to strike, don't make the ceremonial cup of coffee or have to find your writing pen. Don't get caught up in the trap of the writing ritual. Wherever you are, whatever's around you, just lace up your shoes and go.