In order to increase your vocabulary, you will have to read a minimum of one book and multiple magazines every week for the rest of your life. When you discover a word that is not known to you, the best technique is to halt reading and make an effort to pick out what the meaning could be based on its context in the sentence. Focus on how it appears and its sound. Then look up its meaning in the dictionary. As you do this, you may discover that the word keeps appearing more often as you continue with your reading efforts.
A further method is to make sure that your mind is open to new ideas and concepts because each and every word represents a new notion. You may have to look for those fields of human knowledge that are still new to you, like semantics, psychology, music and art. After choosing the specific field that you find compelling, you can start reading book on that individual subject. This will provide you with a greater understanding of the subject and allow you to learn new words as you continue to expose yourself to it.
Your next step is to let your newly discovered words to linger in your mind. One way to achieve this is to apply them in your writing or in your speech. As long as you apply them appropriately, no one will notice that you have been adding to your vocabulary. If anybody does notice it and attempts to discourage you, remember to keep your mind focused on your goal because the next strategy is to form a goal of how many new words to add to your vocabulary each day. While this may seem to be difficult and ambitious at first, you may soon discover that the process becomes easier each day that you practice it.
It's a good idea to also seek out websites that help with building your vocabulary. There are plenty of web based resources that can assist you. You can also try doing crossword puzzles and other word games.