Quiz your elementary school students on the spelling of key words and themes in the novel such as "handicapped," "soccer," "hero," and "athlete" to name a few. For the more advanced student (e.g., junior high or high school) give a "Thesaurus" quiz using similar words. For example, instead of asking an 8th grader to spell "athlete" ask them to come up with a list of words that mean similar things.
For younger students, develop a worksheet that lists key phrases taken from the novel and have them "fill-in-the-blank" with their own mini-story or conclusion. Have students practice starting and ending sentences and making compound sentences.
Make a list of key terms from the book and ask your students to first define the term and then use it in a sentence. You can make the list of terms easier or harder depending on your students' ability. Some key words from the novel include "koi," "deliberately," and "perimeter".
Games are a great way to make vocabulary fun for students. For example, you might write down key words from the novel on index cards. Each student gets one index card with a word. Call out a definition and the student who thinks they have the correct word should announce it. In order to get full points, the student should be able to use that word in a sentence of their own using the characters from "Tangerine."