Subject Knowledge
The surest way to be taken seriously in Germany is to know your subject in depth. Colleagues listen to the person who understands the technical detail, not to the smoothest manner or the most senior title. Fachkompetenz, proven command of your specialist area, is the foundation everything else rests on. Germans will test it, so expect detailed and probing questions. Vague answers quietly cost you standing. Depth beats breadth, and the recognized specialist is trusted more than the versatile generalist. The upside is that your credibility is largely in your own hands, and it travels with you regardless of whom you know.
Reasoning
Being right is not enough in Germany. You have to make the thinking visible so others can follow it and check it. Germans value Nachvollziehbarkeit, a conclusion that can be reconstructed step by step. Assert something without showing how you got there and you will meet pushback even when you are correct. So walk colleagues through the logic. The data, the trade-offs, why the alternatives were ruled out. Trust me carries no weight. Here is the reasoning and here is the evidence carries a great deal. Once the reasoning holds up, the position is genuinely accepted rather than merely tolerated.
Substance
Direct disagreement is normal in Germany and it usually builds standing rather than damaging it. The idea is Sachlichkeit, keeping the matter separate from the person. Saying plainly that something will not work, and why, reads as engaged and competent. Voicing concerns is constructive. The same logic means credibility comes from the substance of the work and not from charm, networking or self-promotion. The colleague who quietly does excellent work is trusted more than the polished presenter, and obvious Selbstdarstellung backfires. Warmth and likeability will not substitute for being right.
Qualifications
Credentials matter in Germany in a concrete and durable way. A doctorate, an engineering degree, a Meister certificate or a recognized professional qualification is a verified marker that opens doors and grants immediate standing. Titles appear on business cards, on name plates and in how people are addressed. They are not decoration. Many trades and professions are legally tied to formal qualification, and misrepresenting a title is a serious matter that can end a career. Understand how credentials interact with ability. The qualification gets you into the room and grants initial trust. Demonstrated competence is what sustains it, and a title with nothing behind it is quickly discounted.
Reliability
Reliability is a major and steadily accumulating source of credibility in Germany. Verlässlichkeit means keeping commitments precisely. Delivering what was promised, to the agreed specification, by the agreed time. Punctuality is part of it, because being on time signals that you take the obligation seriously. Credibility here is built slowly through a consistent record, and one clear case of over-promising and under-delivering sets you back a long way. Promise conservatively and then deliver in full. One honest nuance. Germans hold reliability as a strong ideal and sometimes fall short of it, and the trains are a standing national complaint. At the level of individual colleagues the expectation is genuinely lived, and people remember who keeps their word.
Thoroughness
Thoroughness earns trust in Germany. Gründlichkeit means doing the work completely. Considering the edge cases, documenting properly, leaving no loose ends. The colleague who has thought a problem through to the end, anticipated the complications and can handle the follow-up questions is trusted more than the one offering a quick surface answer. This is why German work prioritizes completeness over speed, and why a polished but shallow piece lands worse than a slower and exhaustive one. Expect detailed scrutiny when you present something. Visible depth and care read as seriousness, and seriousness is what makes you worth listening to.