Start by plunging the clogged sink drain. Use your toilet plunger (well-washed), if you have to. A dedicated sink plunger is better, though; it’s smaller and flat-bottomed — unlike a toilet plunger, which ends in a flange. Plunging alone may be enough to take care of clogged drains. Even if further action is necessary, at least you’ve gotten rid of all that standing water first.