Those who are looking for improving their English esp. word power for exams like GRE, SAT should visit NYTimes and read articles on language written by William Spahire.
In every article, he picks up a word, part of some news, and discusses etymological evolution, usage in various contexts. You will also learn at least 7-10 good , if not new, words. By good I mean words rarely used by an average English literate.
I gave my GRE and scored 600/800 in Verbal.
I had mugged up 3500 words [Barron's wordlist], mostly alien to me in one or the other way in around 3 months time, on an average 2 hrs a day.
Though I could retain 2800 just before GRE.
I would like to share the strategies I tried to attack my weak vocabulary
These days newspapers like TOI consciously present them(esp. their editorial section) with a focus on students preparing for competitive exams involving strong English vocabulary.
Though its a well known fact that editorials usually involve unusual vocabulary, TOI takes special care by ensuring that its articles covers words from Barron.
All About Words: An Adult Approach to Vocabulary
I read first 4 chapters of this book and it was real enlightening.
It helped me build an appetite for words
Another thing that acted as a friend, philosopher and guide were the 2 dictionaries that I bought
Oxford Advanced Learner's Dictionary
Oxford Illustrated Dictionary
They helped me understand subtle differences in words and fine shades of their meanings.
I literally sat for over 600 words and read from the dictionary. But give the time constraint, I could not continue this exercise for all words.
More later .... need to run for dinner