Mixed metaphor aside, Heather is right. Everyone's path through the forest of plot design is different. It really depends on the type of story you are telling. What is most important to you?
Do you have characters in mind, and want to see what becomes of them? Do you instead have a bulleted outline of events that need to happen to tell a cohesive tale?
Or maybe you're somewhere in between, where your best approach is to do a light pass of each, like a slow form of ripple-shuffling. Spending time on one side learning details that will inform the other, then do the alternate pass. Repeat and rinse until it all comes together. (You'll eventually find there are more than two sides, but details,)