Keep a notebook of new words you encounter during everyday life. Look up the definitions of the words, and write them in the notebook as well. Look over the entire list once a week to keep the words fresh in your memory.
Record unfamiliar words you hear while watching television or movies in your notebook, adding their definitions once you have access to a dictionary.
Read books and magazines that challenge you. When you come across an unfamiliar word, and it to your notebook list and look it up in the dictionary.
Pick one of the new words you have learned, and spend a day focusing on it. Choose a new vocabulary word each day. Try to use the word as often as possible, both in written work and in conversation. Using new words will increase the likelihood that you remember them.
Play word games, such as Scrabble. Pulling words to use from your memory will help keep your new vocabulary fresh. If you're playing with a partner, you may learn new words from them, as well.
Write a vocabulary word on one side of an index card, and write its definition on the other. When you have free time, run through the flashcards and quiz yourself on the words and their meanings; this will test your vocabulary and exercise your memory skills.