Find a list of English prefixes. Web sites such as Some Zozanga.com, Learnenglish.de and Englishclub.com have extensive lists of English prefixes and their meanings. Take some time to read over the list and make a note of any prefixes you might have difficulty remembering and which words they augment. Your dictionary may also have a list of prefixes listed alongside full words.
Take notes while reading a book. Whenever your encounter a word with a prefix, look it up and write it down. This will help you build your vocabulary. Try to identify the word on your own before looking it up. Try to recognize the base word and guess the meaning of the prefix from the context.
Download an app for your smartphone. Programs such as Prefix King, Grammar King and PrefixSuffix have extensive lists of English prefixes. These programs have definitions along with explanations of the prefixes' origins.
Try practice activities. Applying what you have learned will help reinforce your memory and show you practical ways of using prefixes. Practice activities are available in ESL books, grammar textbooks and Web sites.
Review your prefix list regularly, and apply it. It is easy to forget what you have learned if you only look at it once. Look at your list of words minus the prefixes, and see if you can remember which prefixes you can use. Try to use them in your everyday speech and writing.