Here's a thought: No Dictionaries! Use the living dictionaries in your classroom, the students. If a student doesn't know a word, ask someone in the class to explain it in English by using synonyms, antonyms and examples. Direct translation (i.e., giving the Mandarin word) won't help the students retain the new word. They're going to have to 'work for it' if they want to remember it.
About teaching vocab, Association is a great way to learn new words in a fun way. Write a word on the board, circle it, and ask students to brainstorm all the things that come to mind when they read or hear the word. You can also do the opposite: Disassociation.
One of the best ways I've found to get students motivated into wanting to learn and retain new words is to choose a topic that interests them. Here's one way to start: pair students up and have them write mini-dialogues. No Dictionaries allowed! If they don't know a word, they have to ask another student.
You can add to the task by giving the students a list of words that you know they don't know. Label the words as noun, verb, adjective, and so on so they know where to use them. Have them pair up and write a mini-dialogue using those words. The objective is to get the words wrong; that is, they are supposed to guess what they think the words mean. After the pairs are done writing, they present their dialogues; after the first pair has presented, you, the teacher, goes over some of the words, not all, giving their meaning with examples. Then the next pair presents, errors and all! The result, an attentive audience and loads of laughter. They will retain at least half of the new words, if not more.
All the best.