A one-step solution for all my vocabulary needs are met through dictionary.com. I have bookmarked the website on all my browsers at work as well as at my residence. This is one very convenient approach for finding not just the meaning of the words you are not aware of, but there are a list of synonyms that you can use while drafting anything, so as to avoid being repetitive and lay a good impression on the readers of whatever I write.
I receive a lot of compliments and positive feedback for the rich set of words that I use while writing or while talking. And my secret to it is dictionary.com. One of my teacher at school had told me that I should decide and learn something new everyday. This was a very convincing idea that influenced me greatly and was engraved on my mind. After a lot of thinking, I decided that I will start from learning at least three new words each day. This website has helped me achieve this goal very easily, because of its column titled - Word of the day.
This is not it. You will find a rich thesaurus, quotes, references, translation, etc., out here. Using this website makes you proficient in your language, which also helps in developing confidence while speaking, and confusing people in debates.