First what's needed, is a basic understanding of what the weak points are in the particular engine under discussion, for the application in question, and what would be beneficial to change (even if it's not a "weak point" as such).
What would be a weak point in one set of circumstances might not be the weak point in another set of circumstances, you have to consider the application. If someone doesn't want massive revs but does want massive boost pressure, they're going to run into a different set of issues than someone who wants to rev the engine to the moon.
If the weak point is the rods, you use stronger rods. If the weak point is the head gasket, you O-ring it. If rapid acceleration is called for, you lighten moving parts. If high revs are called for, you balance everything to reduce vibration.
This is not a simple business, because frequently what's done as a countermeasure for one issue creates other problems that have to be dealt with in turn.