AbyssGames planning, planning, planning!
It's your first project so it's ok but without a more professional approach you won't go very far! I mean if your plan is a living from this kind of work...
Write down your characters, write down a skeleton of the whole story (with all important highlights) do some story boarding, cut out the chapters and keep it on rails following the plan.
Before the "real work" (aka writing the script and generating the pictures chapter after chapter) you must know how many images, how many lines, how many time it will take. For each chapters. And you must have an end date for the project.
If you can do that you will have a much longer career than most devs around...