Researching the domestic laws of a foreign country, or implementation at the national level of international obligations, will be different pretty much every time. Unfortunately, there is no one comprehensive database for searching all the laws of every country, although some resources exist that cover multiple countries for certain jurisdictions, or for certain topics (e.g. tax).
As laid out in the general strategy here, your first steps should be:
If you are having difficulty finding the law, or at any point in the process above, please contact Gabriela Femenia, Biddle's Foreign and International Law Librarian, for help getting what you need!
Before trying to find and read a country's law in a given area, you must understand that country's legal system and, if appropriate, the specific area of law as well. A good introduction to that country and/or area of law will help you understand what the essential sources of law are in that jurisdiction, how they get made, and how they are enforced.
Biddle has legal system overviews and introductions for most countries and subjects, so begin by checking LOLA using terms like "legal system (country)". A few examples of useful books and e-resources are listed here. A good research guide will most likely also point you to useful introductory material on your target country.
German Legal System and Laws by 
The Legal System of the People's Republic of China in a Nutshell by 
A good research guide, research manual or finding tool will help you identify the right database or website for finding the law, many of which will be accessible through Biddle's E-Resource list. These are just some of the most frequently-used sources for multi-national research.
A quick note about Lexis and Westlaw: They are excellent for some jurisdictions (e.g. the UK, Canada and Australia), and not very good for others (particularly non-English speaking countries in the global south). For most jurisdictions, they will only offer a handful of law reviews or other secondary sources. Check the available content, but do not be surprised if there is very little, and turn instead to a specialized database, government site, or other tool recommended by the research guidance you've found.
Whether you're new to a jurisdiction or just not sure you know the most efficient way to research, a good research guide can save you enormous amounts of time and frustration. A good one will also provide at least some introduction to the jurisdiction as well as pointing you to the right websites, databases, and publications for that country, and some will even give you annotated bibliographies of the best secondary sources to look at.
The links below will point you to some of the best research guides for national law research. If you don't find the information you need here, a judicious Google search for "legal research guide [your country or topic] will often turn up the right guidance.
Additional Sources for Guides
Libraries with big foreign law collections also tend to be good at producing research guides, e.g. Georgetown, Harvard, Columbia and Yale in general, and University of Washington for Japan, Korea and China. Biddle currently has guides on human rights, treaties, and rule of law.
Country-Specific Research Manuals
For some jurisdictions, you may be able to find a detailed legal research manual prepared for researchers or practicing attorneys. This is most likely to be the case for common-law jurisdictions like the United Kingdom or Canada, but some are also available for other countries, e.g. China. Check LOLA to see if one is available for your specific country or topic.
For a guide to the best databases for a given country, consult a good research guide, the Foreign Law Guide, or NYU's list of databases by country. Please not that some will have little or no content in English, and will require that you read the native language in order to make use of it.
Some of the main country- or region-specific databases Biddle subscribes to are listed here. Most do not require a separate login/password, but please email Gabriela Femenia if you have access issues, or would like help navigating the database.
After getting your bearings in the legal system and the subject area, a finding tool can help you locate the sources of law on your topic or country. The Foreign Law Guide is an excellent first step, as it provides both an overview of the legal system and its sources of legal information, and an index of major laws by subject. If you do not have access to this subscription database, the Law Library of Congress is a great, free second choice.
For even more specific coverage of your topic, locate a treatise, handbook for practicing attorneys, or other secondary source in Biddle or your nearest law library.
Sources of State Practice in International Law by Finding a relatively recent, reliable translation of a foreign law is going to be a challenge in most cases. Some types of law are more likely to be available than others (constitutions are most likely, business statutes are the next most likely), and some countries are better than others (Germany's Ministry of Justice is a generous global citizen, as is Japan's).
Start with the Foreign Law Guide, and also check the Law Library of Congress's helpful guide to translations for certain jurisdictions. Beyond that, here are a few sources that may prove most fruitful: