joshua - workflowy.com
put down what needs doing in broad steps
then break it down into what needs doing like, coming up with idea, testing idea, making basic gameplay, starting art, etc
then break them down either as you go, or all at once into further steps like phases if you need to, or not if you don't. the idea though is if the list seems overwhelming you can click the circle on the left and fill the screen with only one section and it's subtasks, and if they are too big and still seem overwhelming to start on, break them down even more until you're like "seriously? I can finish this in two minutes"
and if you start crossing those out even one a day
you'd be surprised at how different you feel. trust me I'm an expert on feeling overwhelmed