A clogged bathroom sink is usually caused by hair, soap scum, and buildup collecting under the stopper. Most clogs clear in about 15 minutes with a few basic tools.
Grab the stopper and twist counterclockwise while pulling upward. If it won't come out, look under the sink for the pivot rod, squeeze the retaining clip, and slide the rod out.
Pull out all hair, soap residue, and buildup below the stopper. In many cases this alone restores normal drainage.
Feed the snake into the drain slowly while turning the handle. When you feel resistance you've hit the clog. Twist through it and pull the snake back out.
Run the hottest water available for 30-60 seconds to flush debris through the drain line.
Pour enzyme drain cleaner per product instructions. Most need 15-30 minutes. Heavy buildup may require overnight treatment.
If two full rounds of snaking don't solve the problem, the clog is likely deeper past the P-trap.
Pull the stopper monthly and remove buildup. Run hot water weekly for 30 seconds to soften soap scum before it hardens.