What is the best way to use plumbers putty when installing a sink drain?

The best way to use plumber's putty when installing a sink drain is to apply a thin, even layer of putty around the underside of the drain flange before inserting it into the sink opening. This helps create a watertight seal to prevent leaks. Be sure to wipe away any excess putty that squeezes out and tighten the drain assembly securely.