The simple two-step process
Step one: Open all doors. Learn a little about a lot. Consider as many options as possible, then add more.
Step two: Relentlessly dismiss, prune and eliminate. Choose. Ship.
The problem most people run into is that they mix the steps and confuse them. During step one, they aren't open enough, aren't willing enough to consider the impossible. And then, in step two, fear of shipping kicks in and they stay open too long, hold on to too many options and hesitate.
Simple doesn't always mean easy.