First try the liquid drain products that are compatible with your home plumbing system. Some drain cleaners can not be used with PVC pipe, so read the label carefully. Never unscrew a trap with chemicals present and never mix different types of chemicals. Many are not compatible with each other.
If there is a minor clog, a simple plunger will solve the problem. In case you don’t have one around, try using your palms. Cup your hands over the sink drain to create a vacuum and press down, like you would do with a plunger.
If plunging doesn’t solve the problem, try a pouring a cup of baking soda, followed by three cups of boiling water. This should unclog the drain. You could also try one of the many the drain cleaning solutions available in the market.
And if the drain is still clogged, then insert a stick or rod into the drain and try to push away whatever particles are causing the problem. Be sure to use a slightly flexible stick so you can manoeuvre it around.
Lastly, if all three methods fail, call a plumber – the clog maybe in an external pipeline.