So, you've created your product. Congratulations! You've poured tons of time and energy into it, you've collaborated closely with designers and artists, and you know every pixel in intimate detail. You can see the entire visual picture: UI, characters, locations, vehicles, levels, buttons, settings, menus, reward icons, and everything else.
So far, so good. Next, you export your text and send it to your translator(s). Here's where things start to get off track. Unable to see the parts of the interface in which their translations will be used, translators have to resort to researching your product online (which won't necessarily help) or simply working blindfolded. This is one of the main issues I come across in localization!
The best way to avoid this hiccup is to give your translation team access to your build/application/website along with the files to be translated. Show them screenshots, record walk-through videos for them — in a nutshell, give them as many visual references as possible. That way, your translator can get familiar with the ins and outs of the concept, design, and functionality of your product before they start their work.