Our instinct tells us to fear the unknowns, especially the ones that loom large in our imagination. The bigger the unknown, the more fear and uncertainty it generates, and in some cases it can lead us to paralysis and inability to move forward.
Most often, the only way to conquer these unknown obstacles is to face them head on. Study them, attack them, break them apart, until you understand what they are. Unknowns are often challenging only because they are unknowns. Once you have a deeper understanding of them, it becomes easier to figure out how to proceed to overcome them.
Attack your unknowns.