Using flashcards is an old but effective way to learn new words. Write the word on one side. On the other side you can draw a picture, or write the meaning of the word in English (or Chinese). Keep your cards in sets of ten or twenty related words. For example, animals, parts of the body, etc. Or, nouns, verbs, adjectives, etc.
Study Set 1 until you know it well. Put Set 1 away, and practice Set 2. When you know it well, put it aside and practice Set 1 again. Then go to Set 3. Back to Set 2. On to Set 4. Back to Set 3. And so on.
Keep your cards in your book-bag, or pocket, or pencil case. Take them out and study every time you have a free moment: on the bus, at the break, during lunch hour. You will be amazed at how much you can learn if you do this month after month; year after year.
When you are reading, look for the words you have been studying. Try to use the word(s) when you are speaking or writing. If we use them, we are more likely to remember them.
Steady but sure wins the race. A little every day is better than a lot once in a while.Good luck!