This section is a collection of practical hints that proved helpful in real world translation, team work, building an infrastructure and so on for several language teams. Of course, it is totally up to yourself if you want to make any use of these recommendations.
Everything that's in this section so far, has to do with "consistency" in one way or another. I see this as a main consideration for a desktop system that is trying to keep its look and feel as unified as possible. Similarly, all programs should use the same translation terms in GUI and doc translation. At the same time, achieving this kind of consistency is one of the biggest challenges for writers and translators in projects like KDE.
As always: if you think something should be mentioned in this section but you can't find it yet, just let me know.
Don't work isolated. Talk to your co-translators how your translation should look like and what your target groups are. If your translation is for "ordinary users", including business people, it will look very different from a translation that is made for computer specialists. (Normally, KDE is not being considered as something that's "made only for geeks".) Anyway: try to develop a style guide for your team.
Find standard translations for standard elements and stick to them. The archived PO translations at i18n.kde.org/po_overview will be very helpful in this respect, just like specialized translation programs like Ktranslator, KBabel, or certain Emacs modes that either allow to search these files or provide comparable means to help you with consistency checking. Also make good use of word lists and dictionaries, of web fora and mailing lists.
Develop a system of "mutual proofreading" to make sure that everybody involved sticks to the rules. This can be somewhat delicate at times (so don't be too argumentative;), but since this provides also your best means to correct spelling mistakes and stupid errors you will have to set up such a mechanism anyway, at least in the long run.
It may be a good idea to let the same person do the GUI translation and the translation of the online help (i.e. the documentation) of a given program. If this is not possible, the person who does the final proofreading of the documentation, the screenshots and so on should be allowed to make corrections to the PO files as well, ensuring that GUI and online help are speaking the same language. It is extremely confusing to the users if there are different terms in the documentation and in the actual menus of the very same program.