How to build Vocabulary?

It is a proven fact that vocabulary skills are really helpful in all walks of like. Whether it an interview or a business meeting or a personal alliance or an entrance exam, vocabulary helps a lot. But the question is how to build the same?
One can practice using good words in our day to day conversation. Another way is to associate the words with a picture in your mind. You must keep practicing a lot.
There are several resources available on the internet to develop vocabulary skills. Several coaching institutes also provide such training.