The primary enemies of razor blades are moisture (causing rust) and residue buildup (dulling).

Rinse Well: After each use, rinse the razor blade thoroughly under hot running water to remove all hair, soap, and shaving cream residue.
Dry Completely: This is crucial. Gently pat the razor head dry with a towel (avoiding touching the blades directly) or blast it with a hair dryer on a cool setting for a few seconds. Some people dip the blade head briefly in isopropyl alcohol to displace water and speed drying/disinfection.
Store Dry: Store the razor upright in a dry place outside the humid shower environment. A razor stand or even a cup on the counter is better than leaving it in the shower.

N/A - Focuses on preventing the main causes of blade degradation: rust and buildup.

Rinse, Dry Thoroughly, and Store Dry