If you're translating it for work or something similar, I would pay a professional translator to do it, a western person not a Chinese person. That's the biggest problem in China right now, about 99% of translators are Chinese people so there are ALOT of mistakes when translating from Chi to Eng! In England, a translator rarely translates from English to their second language (on paper I mean...orally is fine). Chinese people should translate from English to Chinese and English people should translate from Chinese to English! Mixing the two only brings poor results.
If you need and Chi-Eng translator, I'm always freelancing :-)

HOWEVER....if you are doing this for school and they are testing your English skills then that is different, you should list all your questions and ask your friends for help IF you can't work it out youself first. One thing I like to do when i write Chinese is put the sentence on to Google if I'm not sure about it. For e.g., if I want to translate "Have you eaten?" to Chinese and I don't know if it is "你吃饭了吗?" or "饭吃了没有?" or "吃饭不了?" etc. Then I take each one, put it onto Google search with " " and see which one gets the most results! That way you can know if your sentence is correct (i.e. there are many results) or if your sentence is wrong (i.e. no results or very few).
When you do this, you MUST go to advance settings and chose English websites ONLY! otherwise you could be learning "bad English" from people who have made the same mistake as you.

Hope that helps.