When translating a document, it’s important that you read through and understand every sentence. It may seem like an obvious point to make, but it can be all to easy to rush through a piece of text with only a decent understanding and translate from there.
It goes without saying that with a better understanding of the document, a better translation will be produced in the end. Understanding the entire document concisely also allows for the flow of the text to be translated more accurately. Something that can only be perceived with a deeper understanding than just the literal translation of the written words.
Lastly try not to rush, take your time and read through the document in a relaxed way. It will set the pace and tone of the final translation and helps make the work easier overall and will also make double checking easier when re-reading the document.