How are you going to evaluate what you find?
Authority - Who wrote it or who is responsible for it? Why should I care what they think?
Try to find the official website for the city, event, place, etc. If you aren't positive it's the official one, verify against other resources, such as a reference in Wikipedia.
Try to use sources that have gone through an editorial process, such as local newspapers.
For websites in general, determine who bears the most responsibility for the information: the individual author or the organization. It's usually more important to judge the authority of the organization who published the information on their website, rather than the individual(s) who wrote it.
Trustworthiness - Is the information sound? How does it compare with other sources?
This is an important criterion to judge your source. But it is the one that takes the most time, because you have to read over various sources to know enough about your issue to judge the soundness.
If it is a major city, event, etc. that you are researching, we may have a published encyclopedia entry on it (though in English). See the tab Background Info for suggestions.
NewsGuard thoroughly evaluates over 8,000 online news sites, including major German ones. Use Microsoft Edge browser and download the extension for free. (Otherwise it's a subscription service, $4.95/month.) Use it on laptops. (NewsGuard claims it will work on the app version on mobile devices, but it isn't in the settings for Apple iOS.)
Adding NewsGuard to Microsoft Edge
Within Microsoft Edge, click on Microsoft Edge in the toolbar, then Microsoft Edge Extensions. Search newsguard and click to add it.
When you click the Get button, it prompts you to create an account in NewsGuard. Click the Sign In button, top right corner, and either create an account or sign in with an existing Apple, Facebook, or Google account.
Once you've created a Newsguard account, it appears to want a credit card for the subscription. Ignore that, scroll down to the bottom, and it says Not ready yet? Maybe later. Click the Maybe later link, and it will add the extension.
Once you have NewsGuard installed, you'll see a green, gray, or red icon next to the results list in Google, or at the top next to the URL when you are on a site that NewsGuard has evaluated. Hover over the icon to bring up a short evaluation of how well it follows journalistic standards. Click on See the full Nutrition Label to view a detailed analysis, with references.