Look at the root word you need to add the prefix to.
Choose the correct prefix to put in front of the word, if you have a choice. For example, if the root word is "fix" and your choices for prefixes include de-, pre- or intra-, pick pre-.
Put the prefix in front of the word to form the new word. In the example, "pre-" would be written in front of the root word "fix" to form the new word, "prefix."
Look at the root word you need to add the suffix to.
Choose the correct suffix to add onto the end of the word, if you have a choice. For example, if the root word is "end," and your suffix choices include -ing, -ly or -er, pick "-ing."
Add the suffix to the end of the word to form the new word. In the example, the root word "end" would become "ending." Determine if you need to change the spelling of the word based on proper grammar rules.