How do I fix a slow bathroom sink drain?

Start by removing the drain stopper, which often traps hair and toothpaste residue. Clean off any debris. Use a drain snake or zip tool to reach clogs further down the pipe. Remove and clean the P-trap under the sink, which collects buildup over time. Pour baking soda and vinegar down the drain, let it fizz for 15 minutes, then flush with hot water. If the drain remains slow, the clog may be deeper in the wall pipe and require a plumber.