How to unblock a sink?

My sink is draining really slow, any suggestions on how to unblock it?

1. Firstly make sure that if the sink is full of water that you put the plug in the drain for the sink or you will get extremely wet.

2. Place a bucket or suitable container beneath the trap underneath the sink and remove the trap, some bottle traps simply twist off and you shaped traps have two retaining nuts.

3. Empty the contents of the trap into the bucket, making sure that the pipes that attach to the trap are clear.

4. Replace the trap and check for leaks, if one of the unions is leaking, wrap some PTFE tape around the thread.

However using a plunger is much easier! =]
*Information taken from http://www.ultimateh..., check it out, it may be helpful*

drain-o works pretty good.

I've tried dumping half a bottle of drain-o down the sink, it didnt do anything...

DRAIN-O or any unblocking agent... which can be found at any local store.. [WALMART/KROGER/ALBERTSONS/DOLLAR TREE]