How do I unclog a slow drain?

Start mechanical, not chemical: remove and clean the stopper/pop-up (hair is the usual culprit), then use a drain snake or a bent wire, and finish with a plunger. Boiling water + baking soda/vinegar helps grease clogs. Avoid harsh chemical cleaners — they can damage pipes and rarely fix hair clogs. If multiple drains are slow, that points to a main line and needs a plumber.