In addition to using prefixes and suffixes, you can increase your vocabulary by analyzing contexts and reading actively.

If a word is at first unfamiliar to you, look carefully at its context, paying attention to all the clues the context provides; often, you will be able to deduce the meaning. For instance, if the word accoutrements is unfamiliar in the sentence We stopped at a camping-supply store to pick up last-minute accoutrements, the context—a camping-supply store and last-minute—suggests strongly that equipment or some similar word fits the bill. And that is what accoutrements means.

When you are studying a new field, you may encounter words that are completely unfamiliar to you or that have a different meaning in the field than they have in everyday use. You may want to keep a log of new vocabulary in your chosen field. (See also 19d and 30a.)