In order to effectively translate and understand a new language, you are also quite dependant on your understanding of the other language. Don't limit yourself to basic vocabulary in either language, learn more words that help file down meanings to more specific things.
Beyond this, there are certain things that simply can not be translated. Some concepts there are words for in the Chinese language, there won't be specific words for in English and vice versa. When you need to translate an English word that doesn't have a Chinese equivelant, you need to understand the meaning of the words. It's not good enough just to know the translation of the words into Chinese, but to understand the concept in English rather than the concept of the translation in Chinese.
Beyond that, practice is the key. The more time you translate, the better you'll get at it. Just be sure to check and make sure your translations are correct.