Once you have mastered the top-down ("is this really the minimum? Or is it a local minimum?") approach, then you could attempt to bottom-up with an end product very firmly in mind. This way, you could skip aiming for parts that you might have thought required which were in reality redundant, or secure the existence of a piece you had once thought superfluous.

After you had bottom-upped a few times, one might even try to figure out a necessary order for the steps and possibly gain some more insight into evolution that way.