You need to make sure that you have the best version of the text. This might mean getting more than one printed text. Try to find pdfs because there are many online. Check and keep checking the text. Do this before doing any translating. You need to make sure of this before setting off. If you do not then you might be setting sail with a boat with a hole in it. I mean a text with lots of mistakes.
There comes a point that even the most battle hardened translator must ask someone. Using commentaries is the best option, if you have access to them. There are many books available online.
The translators English needs to be as high as possible. So further studies in basic English are needed for some. Even a poor translation has benefits but a stronger translation means the text will sell better than a weak one. Reading classical English texts can help one form sentences and so forth. That is the inexpensive method of improving ones English.
The important thing about translating is the actual text. The first question you must ask yourself is: has it been translated before. If it has then do not touch it because no one will pay or publish the work. If you are paid by a publisher then go ahead but if you are doing it yourself then do not bother. The only exception would be if the text was very poorly translated. Even then you need to find a publisher.
Once you have chosen a text then spend a long time searching for previous translations.
If you are relying on a publisher then know that they take their time and can pull the plug at any time and keep the money. So get a contract between you or you might get a shock.
Most publishers are interested in money alone. So consider self publishing because you could be waiting for years for some publishers and even then they could pull the plug on the project and leave with no reward for your work.
Most students of knowledge, as well as many others, want to see the original Arabic sources. The problem with this, is that people want the vowels present. Sometimes, the Arabic text does not have the tashkeel.
They are often people who are interesting in making money and not in paying the translator. They often exploit the work by not paying royalties and not paying anything for the work.
I often get tired of dealing with publishers because of their slow work rate. This is often due to the fact that they are working on more than one work at a time. Your work is often a long way down in the priorities. So you have a choice either to self publish or wait for years for the publisher. You can publish on the internet via text sharing sites such as scribd or kindle ebooks. Keep the rights of your text and keep the copyright. Publishers often do not care about the rights of the translator nor are they concerned with law.
Review the texts after a few years and try to improve them, if its possible.
I hope this is useful for budding translators because its a small minefield and there is a distinct lack of professionalism in the book publishing market. Most people want to make money and will do it any cost. The publishers in particular. Most of them have nullified their good actions.
Yet, they are unaware that sincerity is paramount in any Islamic activity and the lack of sincerity means the reward is nullified. For such people its better to have the intention and not do any Islamic work. Than to do work with bad intentions such as earning money. The work needs sincere intentions and if there is not then it entails punishment because of the exploitation of others, and taking money from people unjustly.