What are some "taboos" of german writing? By "taboo," I mean things that aren't necessarily incorrect, but are considered poor writing or sound wrong. For example, it generally hits the native-english ear wrong to use two adverbs ending in "-ly" in a row (or in close proximity). Also, could you give a quick word or two about why the taboo is a taboo (ie, does it sounds bad/clunky or what the problem with it is exactly) and how one typically resolves/avoids this?
Taking up a suggestion by Jonathan Scholbach in one of the comments above, here is the ultimate solution for learning good style in German writing:
Ludwig Reiners: Stilfibel. Der sichere Weg zum guten Deutsch. First edition Munich 1950, since then many new editions.
Although published already in 1950, this book is your best friend for learning about the pitfalls of style in German writing (and the rules of good style) even today in the late 2010ths.
The book offers many examples of bad style (taken from real-life texts such as business letters, offical documents, poorly written novels and so on), sorted by categories, and offers then solutions for how to phrase those sentences or paragraphs better. It is an entertaining read, as many of the examples are funny. And the suggested edits are often enlightening. To the effect that one is quickly motivated to do the suggested exercises.
Okay, starting from this we could of course list here a number of Reiners' advice:
Don't add adjectives to everything. Sometimes a beautiful noun without an unnecessary adjective is more powerful. Uh... I wanted to say: sometimes a noun without an adjective is more powerful.
Don't build Schachtelsätze, i.e. sentences like Russian dolls (which German is predisposed to, somehow). Reiners gives good advice how to disentangle such boxed sentences.
Avoid Kanzleistil, i.e. bureaucratic expressions (e.g. zur Anwendung bringen instead of simply anwenden)
Use active, not passive clauses! (Or if the joke is allowed: Passive should not be used!) Exceptions are possible, but you need a good reason.
... and 56 more of them. He actually presents this in form of
20 things to avoid - in order to get to a writing style without actual mistakes
20 things to do - in order to get to a writing style with quality
20 more complex things that help writing not only correctly and high quality, but also with effect and impact
For seeing examples, buy the book! You will find it for almost no money in the various second-hand book shops all over the internet and other places. I recently bought 3 or 4 of them for 50 eurocents the piece. But I would have paid 20 euros, if that was the only way to get them. This book is worth it!
Style-issues of mative speakers versus non-native speakers
But, of course: this book was written for native speakers of German, i.e. for poeple who grew up immerged in a culture of speaking German, including all the typcial stylistic blunders.
Users of German as a secondary language will typically make other mistakes; interestingly more related to actual grammar, not style.
Many of my non-native-German-speaking friends have a beautiful writing style naturally because they had not been exposed to bad style at first hand; second, they don't know the usualy clichés, and thus they do not use them. Third, by inferring figures of thought from their first language, they actually produce high quality texts in the sense of creative, unorthodox writing automatically, and withoug even knowing it.
Excursion into one pitfall for non-native speakers
If you come from a language without definite/indefinite articles (or some similar concept), then the first advice for you: pay much, much, much attention to the use of definite/indefinite articles. It is never
Ist Bad frei? :-(
(as my Slovenian flat mate always says)
Ist das Bad frei? :-)
Rule: In singular, use always an article.
Kann ich das Brot haben? :-)
Kann ich ein Brot haben? :-)
Kann ich Brot haben?
is a valid sentence only when Brot definitely has not had appeared in the communicative context before. But this is already an exception. You can never say
Kann ich in Bad gehen? :-(
It is always either ins (in das) or in ein.
We are here, of course, in the no-man's land between grammar and style.
- relative clauses with "dass", especially "dass das", akin to English "I think that that 'that' that that man had used was superflous". It's everywhere because it flows well, and it could always be avoided with effort, that is hard to predict. It's rarely found in laws for example, but frequently otherwise.