Some days to improve your vocabulary:
1) Get familiar with Latin and Greek roots, prefixes, and suffixes. Once you get the basic building blocks, you'll start recognizing them in other words.
Here are some good books to get (they include etymologies - study of word origins):
30 Days to a More Powerful Vocabulary
http://search.barnesandnoble.com/30-Days-to-a-More-Powerful-Vocabulary/Wilfred-Funk/e/9780671743499/?itm=22
Word Power Made Easy
http://search.barnesandnoble.com/Word-Power-Made-Easy/Norman-Lewis/e/9780671741907/?itm=14
2) Read, read, and read! Of course, you should read literary classics, but find something you like to read. It doesn't matter what you read. If you're interested in sports, read the sports page. If you're interested in comics, read comics. Reading words in context will help you understand their meanings.
3) If you are more of a visual learner, write the word on an index card and draw the meaning. That way, you can link the word and meaning together.
4) Say the word aloud, spell it, and visualize it.
5) Use the word in a sentence.
6) Put the definition into your own words.
Good luck!