There is obviously no such thing as a perfect translation and quality will depend on a range of factors including how strong your language skills are. That said, by approaching the task in the right way you can certainly make the translation as good as you possibly can. That, after all, is all anybody can ask.
Everybody obviously has their own way of working but let me tell you about TJ, a top English translator and THE most demanding proofreader I’ve met. His process goes something like this:
1) Read through the source text;
2) Search for parallel target language texts to get a feel for terminology and style;
3) Translate the source document (typically using Trados and where possible with a MultiTerm glossary attached);
4) On-screen review against the source text;
5) Paper review against the source text;
6) First user target language read-through.
This 6-step approach mightn’t work for everyone but it certainly is a starting point. If you feel you might be able to improve your work process, then sit down and work out a method that might help you achieve that. In a time when many clients are looking to cut prices, it is imperative that the quality of our work be as polished as possible, to prove your worth.