I agree completely with Sajid, there can be no shortcut in vocab building.

When I'm reading something I keep a register and a dictionary handy (I use the dictionary I've installed on my mobile phone), and note down the new word I've read, look it up in the dictionary and note down it's meaning, and most importantly I try to make atleast ONE sentence of my own using that new word I've learned in my register. In this way I can remember not only the meaning of that word, but also in what context it is used, so that I can use it when I'm writing something (essay, paragraph writing, etc).

Try it sometime, hope it helps.