The key is to make sure you address any possible concerns / problems that you forsee. This is where decision points are most easily solved, so confront them and resolve them here if at all possible.
Also, an important benefit of this is that the "outline planning" can be done on paper, even if the eventual work will be done on computer or in some other fixed position. For internet addicts, this is a good thing, since it lets you stay off the computer. More generally, sometimes it's good to work in a different location to "get out of a rut", especially if your work area is in your home.
Of course, this is just applying the design stage of engineering to non-engineering topics. But thinking about it as an iteratively-more-detailed-plan makes it easier for me to apply it to many different tasks. Also, realizing it's an optional step, that I can go back and refine whenever I get stuck, I find that helpful as well.