Too Long; Didn't Read
The bigger the task, the more unknown variables you get in programming. Accept the unknowns and accept that you won't know everything. When starting a big task you have to define 2 versions of it. Each piece of your bigger task is a vertical. You don't have to go deep to get the first results. Focus on the main use case or scenario first. The first version is the bare minimum you need to verify that things will work the way you think they will. It will take a lot of time to move from this first, simplistic version to the final version.